Thursday, September 5, 2019

Study Shows Human Endurance May Have Its Limits

The human mind & body are capable of great things, but even the best can hit a wall, new research suggests.

In endurance challenges such as the Ironman triathlon or the Tour de France bicycle race, everyone has the same maximum level of exertion they can sustain over the long haul, researchers found.

They concluded that in grueling physical activities that last for days, weeks & months, humans can only burn calories at 2.5 times their resting metabolic rate. Not even the fastest ultra-marathoners can best that limit.

"This defines the realm of what's possible for humans," said researcher Herman Pontzer, an associate professor of evolutionary anthropology at Duke University.

No one has ever sustained levels above this limit, Pontzer said. "So I guess it's a challenge to elite endurance athletes," he added in a university news release. "Maybe someone will break through that ceiling someday and show us what we're missing."

Above the limit of 2.5 times a person's resting metabolic rate, the body begins to feed on itself to obtain the additional calories needed to function.

The limit may have to do with digestive capability, the researchers speculated. That's why just eating more won't improve endurance. "There's just a limit to how many calories our guts can effectively absorb per day," Pontzer noted.

How Working Out in Anger Can Put You at Risk

Research points to a very long list of benefits from exercise, from improving your overall health to easing stress and enhancing mental well-being. But a landmark study in the journal Circulation highlights a negative, yet specific, concern.

While health factors like obesity and diabetes are known heart attack triggers, data from 12,500 people in 52 countries pointed to two other risk factors to be aware of: exercising at a very high level of physical exertion; and anger or emotional distress.

Either can double the risk of a heart attack. And when combined, they're even more dangerous, tripling the risk. So, while you might take a walk around the block to cool off when you're angry, it's not the time to bench press 300 pounds at the gym.

Does this mean you should never challenge yourself with strenuous workouts? Not necessarily. For an external trigger such as exercise to bring on a heart attack, there probably needs to be an existing problem, like cholesterol build-up in your arteries, researchers explained.

Regular activity is associated with heart benefits, according to the American College of Cardiology. The person who faces a risk from exercise is more likely to be someone out-of-shape who jumps into vigorous exertion suddenly. That's a reminder that the best approach is to start slow, and increase duration and intensity at a slow yet steady pace.

Also, to rein in strong emotions, make stress reduction and anger management part of your heart disease prevention plan. Consider making time for daily meditation, a few minutes of deep breathing twice a day and/or engaging in pursuits that bring you joy.

The Most Effective Way to Tone Your Biceps?

The biceps, the very visible muscles in the front of the upper arms, are a target in every comprehensive strength-training regimen, but what exercise is the most effective?

To answer that question, the American Council on Exercise asked scientists from the University of Wisconsin-La Crosse to evaluate eight popular biceps exercises.

Popular Biceps Strength-Training Exercises

- Barbell curl
- Cable curl
- Chin-up
- Concentration curl
- EZ curl with wide grip
- EZ curl with narrow grip
- Incline curl
- Preacher curl