Elite endurance athletes and exercise physiologists have long known that VO2 max may be the single greatest determinant of athletic performance. But few recreational athletes have access to the kind of specialized lab equipment typically used to assess and train their number. Now a suggests a reliable, yet simpler way to find your VO2 max: An online estimator using your age, weight, sex, waist circumference, resting heart rate, along with data on the frequency and intensity of exercise.

While this tool may work for large populations, it has limited use as a training tool for individuals to track changes in performance and to set targets. But athletes aren’t out of luck. You can estimate and train your VO2 max without setting foot in the lab.

What is Maximum Oxygen Uptake?
The physiology behind your max can get complicated, but it is essentially a measure of your aerobic engine size and just how much blood and oxygen your heart can deliver to your exercising muscles. Because this number serves as the ceiling on aerobic athletic performance, increasing it allows you to perform at a higher level or at the same speed with less effort. For young and middle-aged people, a max of 30-40 ml/kg/min is typical, though this number can be easily boosted with training and weight loss. World-class runners, cyclists, and triathletes are typically in the 70-85 range.

Can Max Be Estimated?
Yes, and you don’t need a high-tech performance institute to do it for you. can help you find these numbers on your own. I contacted Dr. Andy Coggan, a Senior Scientist at Washington University School of Medicine�� and author of , for input:

You can find literature supporting anything from just under 10 to around 12 mL/min per watt as the slope of the power vs. VO2 relationship (i.e., economy) in trained cyclists. In my hands, the average would be ~10.5 mL/min per watt.

This means that you can multiply by the maximum power output (watts) you can sustain for 4-5 minutes on the bike by 10.5 and estimate the oxygen consumption associated with cycling. Account for basal metabolic rate and you get an estimate of max that is within perhaps 5 percent. A simpler way to do it is just multiply the power output you can sustain for 4-5 minutes by 12 and divide by your bodyweight in kilograms.�� ��

Things are a little more complicated with running because the oxygen running speed relationship is much more variable than the oxygen power relationship in cycling. However, if you know your best 10k time, you can make an estimate using this equation from , one of the true pioneers in human performance research.�� Dave founded the world-famous Human Performance Lab at Ball State University and has arguably studied more elite endurance athletes (especially runners) than anyone else.

120.8 – (1.54 x 10k time in minutes)

Using this equation
30 minutes = 75
40 minutes = 59
50 minutes = 44
60 minutes = 28

Make Your Max Rise
Making your VO2 max rise should be one of your primary goals as an endurance athlete. And there are two ways to tackle it: from the weight side of the equation or from the power production side. If you reduce your weight, your VO2 max jumps. So focusing on a sustainable junk-food-free diet is the key to lowering this number.

Equally important but sometimes harder to nudge is your power output. Pushing this number up takes a focused approach, but it also requires a low time commitment, making this one of the best ways to boost your fitness while training indoors as the winter approaches. Three times a week, complete four to six intervals in the three-to-five minute range with up to equal rest. Runners should aim to hit these repeats at their best 5k times while cyclists should target about 90 percent of the power output they can sustain for 4 to 5 minutes.

The gains you’ll see are potentially dramatic. Consider the average recreational athlete in his 20s or 30s. He weighs 80kg and has a 10k personal best of about 46 minutes.�� Using the equation above his estimated max is 50ml/kg/min or about 4L/min. With interval training the power side of the equation may increase 5 to 10 percent. If he drops 5 percent of his bodyweight, or about 9 lbs, he’ll suddenly be in the 56-57 ml/kg/min range—a whole new performance category with a 10k time of perhaps 41 or 42 minutes.

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the past 25-plus years, he’s published hundreds of studies, many of which have focused on how humans respond to exercise. Dr. Joyner also writes at��. The views expressed in his posts are his own and do not reflect those of his employer. 

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It's official. Sugar is killing us—and our economy. With the average American eating 40 teaspoons of the sweet stuff a day, the related health care costs have reached a startling number: . And it's not just limited to the sedentary among us. High-energy lifestyles may not be enough to burn through all this excess carbohydrate. ��

Exercise Is Protective
There’s an old saying that if the furnace is hot enough, anything will burn, even Big Macs. And for dedicated athletes, there’s truth to the idea. With enough exercise, you can probably prevent almost all of the negative health consequences of sugar.�� There are a limited number of studies on the topic, but fit people appear to be . Even in people who are otherwise overweight, exercise reduces the quantity of liver and visceral fat stored around organs that is associated with the worst health outcomes.��

In a recent study, investigators in the UK asked a group of fit young males to stop training and be as inactive as possible while they intentionally overfed them�� with 50 percent extra calories for seven days. Half of the subjects were then assigned to 45 minutes of vigorous treadmill running per day and got additional food to make up for the calories spent exercising��

The inactive overeaters eaters saw their lipids, glucose, and blood pressure all get measurably worse. But these changes were not seen in the group that exercised. The results related to blood sugar regulation were especially striking:

In summary, our study shows that short-term overfeeding combined with reduced physical activity induced a reduction in insulin sensitivity, hyperinsulinemia and altered expression of several key genes within adipose tissue. The addition of daily vigorous-intensity exercise mostly prevented these changes independent of any net effect on energy imbalance. Whether this is facilitated by regular glycogen turnover or some other consequence of muscle contraction per se remains to be explored. These results demonstrate that exercise has a profound effect on physiological function even in the face of a considerable energy surplus.

Exercise is clearly protective. But the interactions aren’t always as clear in the real world as in the lab. A series of new studies have shown that�� at least some people may not respond positively to exercise in the way most of us do. For these non-responders to exercise, too much sugar and too many calories may still pose a legitimate threat to health.��

What About Peak Performance?
Exercise may protect your body from some of sugar’s nastiest effects, but when it comes to peak performance, your bodyweight is a key factor. So while the athlete’s furnace may burn hot enough to avoid the medical problems associated with a bad diet, it’s just not hot enough to let us totally ignore what we eat if we want to go fast.��

That said, most of us live in the real world and don’t have the time, energy, or inclination to eat a pristine farm-to-table diet with minimal processed food and no added sugar. And we don’t need to. Sugar consumption has gone up 25 percent since 1980 as it’s insidiously entered everyday foods. You can cut down to mid-20^th century levels out without reinventing your diet:

1. Avoid routine consumption of sugar-sweetened beverages. And avoid drinking sports drinks on training rides or runs shorter than an hour and a half.�� Water works fine.
2. Replace the high sugar snacks at your workplace with fruit.
3. Read labels. You will be amazed at how much hidden sugar and you munch on. Your morning muffin from Dunkin’ Donuts may pack 49 grams of sugar. And your afternoon granola bar can easily have upwards of 20 grams of sugar.��
4. Your swell Frappuccino Blended can pack 52 grams of sugar. Go black or ask to see the nutritional information before you order.��
5. During the holidays or when on vacation, don’t overthink things. Get regular vigorous exercise and you can afford to overeat.��

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the past 25-plus years, he's published hundreds of studies, many of which have focused on how humans respond to exercise. Dr. Joyner also writes at��. The views expressed in his posts are his own and do not reflect those of his employer.

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What works in the lab doesn’t always work in the field, and sometimes great athletes don’t follow the most recent scientific advice. Coach and distance-running great Alberto Salazar and CrossFit champ Samantha Briggs offer some tips that don’t boast any scientific proof but do contain the ethos of two supreme athletes. Their recommendation? Easy days in-between the pain.

Rest and Recovery
Salazar says:

The day after a tough workout, the most you want to do is jog lightly or do some form of cross-training, like cycling. You need a recovery day after a hard day. No exceptions.

Briggs concurs:

I typically train every day but two of these will be lower intensity or active recovery days. The normal training day will be broken into two sessions, both ranging from two to three hours, depending on loads or intensity of training employed. I try to mix the training up as much as I can. I don’t typically have a complete rest day—I’ll have active recovery days where I enjoy getting out on my bike, going swimming, or skiing.

What is Active Rest?
Active rest is essentially a day of light exercise, potentially with some stretching or form drills—sort of like an extended warm-up. For runners, it might mean 30 minutes of jogging and some faster-paced strides; for cyclists, some easy spinning; and for swimmers, an easy warm-up followed by form drills. The idea is that it takes your muscles 48–72 hours to recover from the micro-damage associated with hard training sessions, so you’ll need to dial it down those few days for your body to catch up. Not to mention, getting the most out of hard training requires the mental energy to really push.

The need for rest is generally accepted but not always applied, as some coaches and athletes mindlessly equate more work with better results. ��

So what does the science say about rest? In short, it doesn’t say much. Most training studies are short-term, lasting a few months at the most. Defining an optimum pattern would take a long-term study on many serious athletes, and determining an outcome wouldn’t be easy. Would success mean a faster time, less injury, a better attitude?

In this case, the athletes may be ahead of the science. Both Salazar and Briggs stress the importance of consistency, and if you’re injured or burnt out, it’s nearly impossible to be consistent.

Recovery and Compression Stockings
Beyond active rest, the endurance world is full of strategies and aids that claim to increase speed or enhance recovery.�� Compression stockings have especially gained popularity. There are a number of good studies on them, with some on running performance and others . One study at the end of a simulated race, but no effect on the race performance:

The change in pre to postexercise jump performance was lower in low and medium compression stockings than in control. Mean heart rate and blood lactate were not different between trials…. In conclusion, GCS worn by competitive runners during 10-kilometer time trials did not affect performance time; however Low and Med GCS resulted in greater maintenance of leg power (vertical jump) after endurance exercise.

This conclusion received support from an :

When compression clothing was applied for recovery purposes after exercise, small to moderate effect sizes were observed in recovery of maximal strength and power, especially vertical-jump exercise; reductions in muscle swelling and perceived muscle pain; blood lactate removal; and increases in body temperature. These results suggest that the application of compression clothing may assist athletic performance and recovery in given situations with consideration of the effect’s magnitude and practical relevance.

In practice, this means that compression stockings could give you a little more snap in the legs and help with the final push at the end of a race. To learn more, I contacted who participates in multi-day endurance events. He, too, has studied the effect of compression clothing. In an extended e-mail, he commented:

As with all of these novelty ergogenic aids, the placebo effect is probably alive and well, and the true effects are generally small and perhaps reflecting some publication bias (for positive results)…. Would have been good to see more of the effects on recovery outcomes done in blinded designs and subjects who’re already well trained in the muscle-damaging interventions! Some of the vertical jump data are for effectively wetsuit shorts, which has the danger of being extrapolated into dissimilar garments.

One-Percent Solution
The effect of compression clothing, if there is one, is small. But it bears remembering that a one-percent edge in a ten-kilometer race is worth 100 meters in distance, and one-percent differences are very difficult to measure in the lab. Much of self-improvement is eking out the last bit of marginal gain in whatever you’re doing: making your bike more aerodynamic, perfecting your swim stroke, tweaking your diet, or investing in light-weight equipment and clothing.

Making These Ideas Work For You
Here are some tips for adding rest and recovery to your routine:
1)���� ��Develop a pattern of “hard day, easy day” and stick to it.
2)���� ��If you have a long day at work or other obligations ahead of you, pre-schedule an easy workout for that day.
3)���� ��Many do more training and racing over the weekend, so consider making Fridays and Mondays designated easy days.
4)���� ��Experiment with compression stockings and other recovery aids—but remember the placebo effect (unless that’s counteractive, in which case, don’t). Truthfully, if technology makes a difference, it is likely small and not a substitute for an easy day.
5)���� ��Multi-sport athletes, beware: Don’t turn the fact that you can train in a variety of disciplines into an excuse to go hard almost every day.
6)���� ��When in doubt, sit on a stationary bike and spin for 30 minutes.

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the past 25-plus years, he’s published hundreds of studies, many of which have focused on how humans respond to exercise. Dr. Joyner also writes at��. The views expressed in his posts are his own and do not reflect those of his employer.

The post When Athletes Know More Than Scientists appeared first on ���ϳԹ��� Online.

Athleticism does you a lot of good, but it doesn’t make you immune to high cholesterol. Up to using either statins, drugs for blood pressure, or drugs for diabetes. Studies show they may have the wrong idea: Statins are known to impair training and cause muscle pain. Thankfully, there are dietary strategies for lowering cholesterol, blood pressure, and blood sugar that work just as well without the risk.

Here are some of the foods that studies have shown can help lower your cholesterol:

So, what would happen if you ate a “portfolio” of these foods instead of taking statins to lower your cholesterol? Scientists at the say you’ll experience much of the same effect:��

We have and continue to carry out research on vegetable proteins and their potential health benefits eg. soy, gluten, and other cereal and vegan proteins. Most recently we have started to combine foods with cholesterol lowering actions (soy, viscous fibers, oats, barley, plant sterols and nuts—almonds) in a single diet to lower serum cholesterol. We have demonstrated that early statin-like effects can be achieved under highly controlled conditions. In the real world this dietary approach has a somewhat dampened level of efficacy, but remains a highly effective dietary approach to cholesterol reduction.

Further Toronto studies suggest this assessment may be a bit modest: In a of 46 middle-aged subjects with high cholesterol, the lipid-lowering effect of one month spent on the portfolio diet was comparable to one month of statin therapy:

The control, statin, and dietary portfolio groups had mean decreases in low-density lipoprotein cholesterol of 8.0%, 30.9%, and 28.6%, respectively…. The significant reductions in the statin and dietary portfolio groups were all significantly different from changes in the control group. There were no significant differences in efficacy between the statin and dietary portfolio treatments.�� CONCLUSION: In this study, diversifying cholesterol-lowering components in the same dietary portfolio increased the effectiveness of diet as a treatment of hypercholesterolemia.

More recently, studies on what adding can do for the portfolio diet have shown added benefits:

Strawberries also improved the palatability of the diet. We conclude that strawberry supplementation reduced oxidative damage to LDL while maintaining reductions in blood lipids and enhancing diet palatability. Added fruit may improve the overall utility of diets designed to lower coronary heart disease risk.

Implications for Athletes
Athletes with cholesterol issues who want to avoid might consider adopting the portfolio diet in place of statins. Statins are effective cholesterol-lowering drugs, yes—but muscle pain is a nasty and fairly common side effect.

Now, statins do reduce mortality in those who have or are at risk of having cardiovascular disease, and statins can be rightfully applied as “primary prevention” even to those with a , as these individuals display few significant side effects:

Reductions in all-cause mortality, major vascular events and revascularisations were found with no excess of adverse events among people without evidence of CVD treated with statins.

However, the studies that made these conclusions did not include a large number of highly active people or serious athletes. In studies of professional athletes with serious familial cholesterol problems, could tolerate statins without muscle pain, and some even showed an increase of short-term muscle damage following heavy exercise.

Statins can be terrific drugs, but we have a limited understanding of how they interact with exercise. To avoid complications, consider the portfolio diet your healthy alternative.

Making The Portfolio Work For You
Here are a few quick tips for incorporating elements of the portfolio into your diet:

1. Try a morning post-workout smoothie with a handful of berries and nuts plus a couple of tablespoons of flaxseed or oat bran.
2. Find the low-carb, soy- or whey-based protein bar that works for you in the case of a snack.
3. Keep some almonds in your desk or backpack.
4. In general, stock your house with portfolio foods. Your default choice will be the easiest, so make it healthy.

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the past 25-plus years, he’s published hundreds of studies, many of which have focused on how humans respond to exercise. Dr. Joyner also writes at��. The views expressed in his posts are his own and do not reflect those of his employer.

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Can you lose weight just by downing a glass of water before dinner? The idea seems straightforward: You drink water before a meal, your stomach fills up a bit, so you eat less. But does intuition stand up to research?

, has recently conducted studies on how drinking water relates to weight loss in people middle-aged and older (for which ). I got to ask Davy what her research means for those of us looking to slim down: Can timing really have that big of an impact?

JOYNER: What have you found is the optimal amount of water to drink before meals if you're trying to lose weight, and what is the best timing?
DAVY: Very few studies have directly addressed this issue. —and found that when middle-aged and older adults drink two cups of water approximately 15–20 minutes before consuming each of their three main daily meals, they eat about 75–90 fewer calories at the meal. When they do this water-appetizer routine daily for three months, while also trying to cut back on their calorie intake, weight loss occurs. Our comparison group lost about 11 pounds, while our water-appetizer group lost close to 16 pounds over three months on average. So the water regimen appeared to facilitate weight loss.

How do your studies of subjects with higher BMIs translate to fitter people who want to drop a few pounds or manage their weight when they can’t train as much as they'd prefer?
We conducted the test-meal water-appetizer studies in both normal weight and overweight/obese adults. Both groups reported feeling more full and less hungry after the water appetizer, and as a result, they ate fewer calories at the meal. So this approach may work for middle-aged and older adults regardless of their weight status.

Have the studies left you with any pressing questions?
One thing we don’t yet know is –who tend to drink a lot of sugary drinks. Even beverages that many people think are healthy, such as Vitaminwater or sports drinks, have calories and added sugar. Water is the best option, in most cases. And many older adults don’t drink enough water. The Institute of Medicine recommends about 9 cups per day for women and about 13 cups per day for men. In contrast, usual drinking water intake in the U.S. is about four cups per day.

Are there any other benefits to drinking water that�� with weight loss?
In addition to the positive effects on food consumption and hunger, . Eat a bit less and burn a few more calories, and it adds up over time.

All of this points to some pretty straightforward advice:

1. Drink a glass of water before meals.
2. Avoid routine consumption of sugar-sweetened beverages (SSBs) (). I'm all for sports drinks when it comes to delaying fatigue and improving performance, but they're only necessary during intense physical training and competition of an hour or longer. Water is your best bet under just about all other circumstances.

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the past 25-plus years, he's published hundreds of studies, many of which have focused on how humans respond to exercise. Dr. Joyner also writes at��. The views expressed in his posts are his own and do not reflect those of his employer.

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All it takes is diet and exercise, but losing weight is improbably hard to do.�� Keeping it off is even harder, and most diet and lifestyle interventions fail. A review of essentially all available came to the following conclusion:��

Long-term multicomponent weight management interventions were generally shown to promote weight loss in overweight or obese adults. Weight changes were small however and weight regain was common.

Why is it so hard to lose weight?

Fatigue Makes Slobs of Us All
Most people live in a low-activity, high-food “obesogenic” world, and it takes constant effort to stay active and eat smart. But why is it so easy to make the wrong decisions? One explanation cites something called . According to this concept, we are confronted with countless choices all day long, but we can only make a certain number of reasoned decisions before our judgment becomes lax.

Many people’s hyper-busy lives have them juggling constantly. As a result, they run out of the psychic energy to consistently generate enough self-discipline to exercise, watch what they eat, and follow health guidelines.��

Roy Baumeister, one of the gurus of decision fatigue research and a professor of psychology at Florida State University, describes the results of a simple experiment involving, of all things, cookies and geometry:

Many studies have found that people perform relatively poorly on tests of self-control when they have engaged in a previous, seemingly unrelated act of self-control. For instance, in a study in my lab, we invited some students to eat fresh-baked chocolate-chip cookies, and asked others to resist the cookies and munch on radishes instead. Then we gave them impossible geometry puzzles to solve. The students who ate the cookies worked on the puzzles for 20 minutes, on average. But the students who had resisted the tempting cookies gave up after an average of eight minutes.�� Such studies suggest that some willpower was used up by the first task, leaving less for the second.

This test helps explain why fatigue from sleep deprivation and are associated with weight gain. In a study using brain imaging to understand those who didn't sleep tended to eat even when they weren't hungry:

Twelve normal-weight male subjects were examined on two sessions in a counterbalanced fashion: after one night of total sleep deprivation and one night of sleep. On the morning after either total sleep deprivation or sleep, neural activation was measured by functional magnetic resonance imaging…. Hunger ratings and morning fasting plasma glucose concentrations were assessed before the scan, as were appetite ratings in response to food images after the scan…. …total sleep deprivation was associated with an increased activation in the right anterior cingulate cortex in response to food images, independent of calorie content and prescan hunger ratings…. Self-reported hunger after the nocturnal vigil was enhanced, but importantly, no change in fasting plasma glucose concentration was found.

These results provide evidence that acute sleep loss enhances hedonic stimulus processing in the brain underlying the drive to consume food, independent of plasma glucose levels. These findings highlight a potentially important mechanism contributing to the growing levels of obesity in Western society.

Tired people are less able to practice self-control than those who get a good night’s sleep. Besides that, they're also more stimulated by what might be described as . (It is hard to imagine anyone craving celery and carrots when they are sleep-deprived.) There is evidence that , too.

All of this is consistent with the idea that we have a limited amount of willpower—and fatigue of any kind impairs our ability to make good choices. This becomes a public health disaster in an environment where the unhealthy choice is frequently the default. For many, it is much easier to choose the drive-through lane than the bike lane.

Managing Decision Fatigue
Here are some tips to help you navigate the decision fatigue minefield we all live in:

1. Work out first thing in the morning before the day catches up with you. Many habitual exercisers do this. They may be inadvertently managing decision fatigue.
2. Get the junk food out of your environment. Fewer decisions will mean less decision fatigue. My wife and I did this in early 2013, and I have now lost 12–14 pounds . Avoid putting the candy in the cart so you don’t have to struggle keeping it in the pantry.
3. Work physical activity into daily tasks. If possible, use active commuting to and from work.
4. Reduce decision making. Think about the routine things that can be made automatic—from what you eat for lunch to where you live. Football coach Nick Saban eats the same thing every day to limit the number of trivial decisions he makes. And I choose to remain in a small city to avoid wasting time driving.
5. Manage your electronic world. For many of us, the day is artificially extended, and sleep time is squeezed by the friend in another time zone or the buddy who’s always online. Most communication can wait. Getting an extra 30 minutes of sleep will help you make the right choices.

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the past 25-plus years, he's published hundreds of studies, many of which have focused on how humans respond to exercise. Dr. Joyner also writes at��. The views expressed in his posts are his own and do not reflect those of his employer.

The post Why It’s Impossible to Just Eat Less appeared first on ���ϳԹ��� Online.

One of the central principles of competitive endurance exercise is that . Extend this to high-volume, high-intensity training and the need for a high-carb diet to sustain daily training seems self-evident. However, there is a lot of enthusiasm for the so-called Paleo Diet which is low-carb and to which a number of serious athletes subscribe.

How are endurance athletes sticking to the Paleo Diet and is there something to low-carb endurance training?

The Paleo Narrative
The big idea behind Paleo is that many of the chronic diseases of the modern world like diabetes, obesity, and heart disease are a result of high carbohydrate intake. According to the narrative, prior to the our hunter-gatherer ancestors ate diets high in animal protein. They also collected nuts, fruits and vegetables. So, if we just turn the clock back and eat a low carbohydrate diet like they did, chronic disease would more or less go away. The Paleo Diet is popular, but it's just the most recent in a long line of low-carb diets that work, mainly because .
��
Paleo is also an interesting story that sound great, but there are holes in just about every element of the narrative. One of the largest ones is that all “Paleo people” shared the same diet.

Low-Carb Training?
Even if the Paleo narrative is flawed, its adherants may be on to something. One of the forgotten classics in exercise physiology is a study done in the early 1980s when five well-trained cyclists spent four-weeks on an ultra-low carbohydrate diet and :

…the mean ergometer endurance time for continuous exercise to exhaustion at 62%-64% of VO2max was 147 minutes at EBD-1 (after high carb diet) and 151 minutes at EKD-4 (after low carb diet). The steady-state RQ dropped from 0.83 to 0.72 (P less than 0.01) from EBD-1 to EKD-4. In agreement with this were a three-fold drop in glucose oxidation (from 15.1 to 5.1 mg/kg/min, P less than 0.05) and a four-fold reduction in muscle glycogen use (0.61 to 0.13 mmol/kg/min, P less than 0.01). Neither clinical nor biochemical evidence of hypoglycemia was observed during EKD-4. These results indicate that aerobic endurance exercise by well-trained cyclists was not compromised by four weeks of ketosis. This was accomplished by a dramatic physiologic adaptation that conserved limited carbohydrate stores (both glucose and muscle glycogen) and made fat the predominant muscle substrate at this submaximal power level…

The cyclists adapted to a very low-carb diet and could go a long time without many carbs. This study suggested that a long period of low-carbs might increase the ability of the muscles to burn fat. This may sound like a minor point, but this strategy might ultimately allow athletes to save their glycogen stores for when they were most needed, potentially providing a race-winning boost. showing about 10 days of a high-fat, low-carb diet improved performance when carbs were fed for three days prior to a long ride followed by a 20k time trial:

The HFD-CHO (High fat followed by carbs) diet increased total fat oxidation and reduced total CHO oxidation but did not alter plasma glucose oxidation during exercise. By contrast, the estimated rates of muscle glycogen and lactate oxidation were lower after the HFD-CHO diet. The HFD-CHO treatment was also associated with improved TT times (29.5 +/- 2.9 min vs. 30.9 +/- 3.4 min for HFD-CHO and CTL-CHO (control diet). High-fat feeding for 10 days prior to CHO-loading was associated with an increased reliance on fat, a decreased reliance on muscle glycogen, and improved time trial performance after prolonged exercise.

There have been a number of additional studies showing more fat and less carb use during exercise, though not all of them show an improvement in high-intensity performance. Taken together, these studies lead to the concept of “dietary periodization” for endurance athletes with the goal of increasing fat utilization and making glycogen stores last longer.

One such strategy is “fat adaptation”, an intervention in which well-trained endurance athletes consume a high-fat, low-CHO (CHO=carbohydrate) diet for up to 2 weeks while undertaking their normal training and then immediately follow this by CHO restoration (consuming a high-CHO diet and tapering for 1-3 days before a major endurance event). Compared with an isoenergetic CHO diet for the same intervention period, this “dietary periodization” protocol increases the rate of whole-body and muscle fat oxidation while attenuating the rate of muscle glycogenolysis during submaximal exercise. Of note is that these metabolic perturbations favoring the oxidation of fat persist even in the face of restored endogenous CHO stores and increased exogenous CHO availability.

Implications for Paleo Athletes
While the mainstream literature supporting the Paleo Diet is scarce, the principles outlined above provide some food for thought for those following a Paleo regime who also compete in endurance sports:

• We don't know if you can do really high-volume, high-intensity training for months or years on a low-carb diet. You might need a least some carbs a few days a week if you intend to do high-intensity traditional interval training. If you are more or less chronically bonked from no muscle glycogen the quality of your training and ultimately you conditioning might suffer. For these reasons make grudging exceptions for hard-core endurance athletes.
• The studies reviewed above were well controlled and the subjects were monitored. Take it slow if you want to cut your carbs. Hitting the wall and bonking are no fun.
• Eat carbs prior to competition and practice any eating or drinking strategies outside of competition. There is a lot of individual variability in how humans respond to dietary changes, find out what works for you. ��

I am a skeptic about diets and fully expected to write a post saying that training while on a low-carb diet (including Paleo) was nuts. However, the data speak for themselves and dietary periodization is another nutritional tool for those who want to go faster and farther in competition.

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the past 25-plus years, he's published hundreds of studies, many of which have focused on how humans respond to exercise. Dr. Joyner also writes at��. The views expressed in his posts are his own and do not reflect those of his employer.

The post The Paleo Endurance Secret appeared first on ���ϳԹ��� Online.

Last week for the 100-mile run when he ran just under twelve hours (11:59:28) on the track. His last marathon (26.2 miles) of the 100-miler was run in less than 3:10! The International Amateur Athletic Federation (IAAF) only recognizes world records up to 100 km (a little over 62 miles), and the best time for 100 miles is 11:28:03 by . Olsen’s average pace was just under 7:12 per mile, Kharitonov’s was just under 6:53.

How are these men and women doing it—running great distances at unimaginable speeds—and is there something special about their physiology?

Everything Except Physiology
There’s more to running an ultra than just endurance. Yes, anyone who finishes an ultra-endurance race must be able to handle high-volume training. But they also have to master the logistics related to fluid and feeding management, equipment, and rest. For some events a support team is required. And for many events, environmental conditions and the course itself are a major part of the challenge.�� ��

Physiology: The same or different?
All of this has led to a lot of speculation about whether the physiological determinants of performance at ultra-endurance events . For ultramarathons, one idea is that . Surprisingly, inefficient running form may lead to less mechanical wear and tear, allowing these athletes to succeed when the distances increase.

Who Sets Records?
One interesting thing to consider is who sets records in these events. by Takahiro Sunada of Japan. Sunada has run the standard 26.2 mile distance in 2:10. He’s clearly an exceptional athlete across distances. The story is the same for women. From what I could glean, . Historically iconic ultra-runners like , , and Barney have all been superb marathoners with personal records under 2:20. ��

Same Story for Swimming
The same trend also holds for swimming. The fastest crossing of the English Channel (6hrs 55min) was done in 2012 by the . Grimsey just missed making the Australian Olympic Team at 1500m in 2008 and his personal best is an impressive 15:12. The women’s record is 7hrs and 25 minutes held by who was also outstanding at shorter distances.

Moving Up Is Hard to Do
These examples all suggest that when fast people move up to longer distances they seem to do very well. And empirical data backs up these observations. When a sample of 93 recreational male ultra-runners was evaluated, their marathon times were strong predictors for their 100 km times:

Results of the multiple regression analysis revealed an independent and negative association of weekly running kilometres and average speed in training with race time, as well as a significant positive association between the sum of eight skinfold thicknesses and race time. There was a significant positive association between 100-km race time and personal best time in a marathon. We conclude that both training and anthropometry were independently associated with race performance. These characteristics remained relevant even when controlling for personal best time in a marathon.

People who did more weekly training, did it faster, and were skinny had faster marathon and 100 km times. This type of data also suggest that the basic physiology of who does well at events as short as 15 minutes applies to ultra-races. I wonder how the East Africans would do if they “moved up.”

And it also suggests that ultra-racers should consider moving down when training to incorporate intervals and even shorter races. Evidently Jon Olsen ran a 1:18 half marathon to get ready for his record attempt.

Ultra-athletes are a mentally tough and highly motivated group who do extremely challenging things.�� What is special about them .

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the last 25+ years, he's published 100s of studies many of which have focused on how humans respond to exercise. Dr. Joyner also writes at . The views expressed in this post are his own and do not reflect those of his employer.

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This weekend, Wilson Kipsang of Kenya He broke Patrick Makau’s world record by 15 seconds. The first recognized world record was 2:04:55 by Paul Tergat at Berlin set in 2003. Prior to that, only “world bests” were recognized.

In light of Berlin, will humans ever crack the two-hour mark?

22 Years and Three Minutes
In 1991, the world best for the marathon was 2:06:50. That year, I published on how fast the optimal human distance runner might go for the marathon. I and both papers suggest that we might someday

So why are Kenyans leading the charge?

The VO2max values and lactate thresholds for the elite East Africans are impressive but not exceptional for world-class runners. However, they are very efficient, allowing them to generate more speed with less oxygen. Their small size might also permit them to thermoregulate better. Finally, a lifetime of physical activity at high altitude can’t hurt.

The graph below shows the projections my colleagues Alejandro Lucia and Jonaton Ruiz made in the updated paper. The faster of the two projections shown in red is based on an average improvement of about 20 seconds per year and the slower blue one is based on ten seconds per year.�� ��

Breaking the Record
A number of people think the sub-two-hour projection is nuts. As I've noted, the improvement to 2:02 might happen quickly—only to then slow down. My rationale: Until recently, the marathon mark was relatively slow compared to the 5k and 10k records on the track, pointing to room for improvement. the current records project out to a marathon time of about 2:02. The other issue is what role doping is or is not playing in all of this.��

That having been said, a targeted world record attempt on a special circuit of a few miles is a fascinating idea to consider. The surface of such a circuit could be tuned for maximum speed and the course absolutely flat. The attempt could be made at twilight on a cool windless evening. To break 2:02 the average 10k pace would need to be just less than 29 minutes, extremely fast but maybe not so fast for a top marathoner who can break 27 minutes.������

If a sponsor put up the right kind of prize money, my guess is we could get very close to 2:02 in the next four of five years and then the chase for 2:01 could start. There are only 204 seconds left to get to two hours. The record continues to fall, and I have not lost the argument yet.

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the past 25-plus years, he's published hundreds of studies, many of which have focused on how humans respond to exercise. Dr. Joyner also writes at��. The views expressed in his posts are his own and do not reflect those of his employer.

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The scientific evidence supporting high-intensity exercise is very solid. This is true for elite athletes, people who are just , and even . Exercise, however, is not risk-free. People do die and have other catastrophic health events while working out.��

What are the risks of high-intensity exercise—and who should be worried?

Heart Attack and Stroke
The big concern is about the risk of heart attack, stroke, or some other catastrophic event during training. This is especially true for people who either have a history of prior events or have a lot of traditional like diabetes, hypertension, high cholesterol, smoking and inactivity.�� ��

There is a that has pioneered the use of high-intensity training in cardiac patients and they report that even in well-screened and monitored patients high-intensity exercise can be somewhat risky. While people doing moderate inensity may experience one event every 15 years, those in the high-intensity group experienced one every three years. At some level, these numbers show just how safe intense exercise can be in high risk groups, but they do point out that rare and potentially catastrophic events are more common with high-intensity exercise.

Middle-Aged Men
The case of , who suffered a major stroke after a high-intensity workout, is a cautionary tale. He had been feeling off his game and interpereted these non-specific symptoms to be signs of stress and poor fitness—intead of the minor story they really were.

Marr isn't uniquie. His story is about a hard-driving middle-aged guy who doesn’t feel right, figures he is out of shape, reads that high-intensity will give him the most bang-for-the-buck, and goes for it—only to have a catastrophic outcome. To me his story is emblematic. The high-intensity approach can feed into the data collection mindset that prolifreates fitness. The potential for misinterpretation by middle-aged super achievers is high.

Who knows what Marr’s history was before his stroke? Had he been a smoker, was he hypertensive, what were his lipid levels, what was his family history… Most of this is simple stuff that could have picked up with a reasonable screening physical prior to starting an exercise program.

Who Should be Screened?
To get some ideas about who should be screened I contacted and an expert on exercise in middle-aged people. Chip still runs an occasional road race and interval trains from time to time. Here is what he told me in an e-mail:

…for middle aged people, particularly those who have been sedentary or with CHD risk factors, they should at least have a physical exam and clearance from their clinician and probably an exercise stress test before doing such hard, intense training -this would not be necessary to do a walking or slow jog program on the other hand. Obviously, this is the kind of exercise young athletes do, so it should be safe for most younger people, certainly for those less than 40…

His thoughts were echoed and amplified by :

…for higher intensity exercise, many individuals should be able to well tolerate this as a form training with some basic assumptions. One that any known health conditions and/or previous musculoskeletal injuries are evaluated and the individual understands that there are increased risks (both cardiovascular and musculoskeletal) associated with this form of training and the individual is willing to accept those risks. And two, that there is a progression to the training.�� In other words, this form of training is not for the novice exerciser, nor is it for one who hasn't been regularly training.�� Finally, there is such a thing as overtraining.

I agree with both Chip and Lenny.

Take Home Messages
High-intensity exercise has many benefits and is time efficient. However, it does carry more risk. Here are some tips to keep it safe:

1. Prepare yourself for high-intensity exercise and build up slowly a few sets and few new exercises at a time. The solution is to sometimes hold back. This can be particuarlly tough for high achievers with world views based on perceptions of their own invincibility.
2. Medical screening prior to high intensity exercise is a reasonable precaution for middle-aged and older people. It is essential for people with risk factors and don't delude yourself: age is a risk factor.
3. If you are having non-specific symptoms of fatigue and feel “not right,” it might be more than a bad day or stress. You could have something else brewing. Exercise and active lifestyle are great but they are no substitute for regular check-ups and reasonable screening tests, especially as you drift into middle age.

There are many reasons to exercise and many reasons to push your limits. With just a tiny bit of moderation it is possible to enjoy a lifetime of physical challenges and avoid a catastrophe. Going to the doctor for a check-up is not a sign of weakness.

Michael J. Joyner, M.D., is a physiologist and anesthesiologist at the Mayo Clinic and a leading voice in the world of exercise physiology. Over the last 25+ years, he's published 100s of studies many of which have focused on how humans respond to exercise. Dr. Joyner also writes at . The views expressed in this post are his own and do not reflect those of his employer.

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