Play Tennis For A Longer Life. Science Proves It.

Chris Evert and former President George H.W. Bush playing
tennis at Camp David during Bush's presidency.

Tennis might just be the best thing you can do to extend your life.

A new study from Denmark, published just last week by Peter Schnohr and colleagues, shows that playing tennis may extend your life by nearly 10 years. That's a remarkably big benefit, one that even the study authors were surprised at.

It's been well-established for a while now that exercise helps you live longer. For example, the Cardiovascular Health Study found that people over the age of 75 can expect to gain 1 to 1.5 years of healthy living by being active rather than sedentary. Others studies have looked at the effects of running or walking and found similar positive benefits.

The authors of the new study wanted to look at other sports activities, not just running. Using a large cohort of 20,000 healthy people in the Copenhagen City Heart Study, they identified 8,577 who were in the study from the early 1990s until 2017 and who met a variety of other criteria for inclusion. This gave them 25 years of followup, long enough to ask the question: how does participation in sports affect life expectancy?

In particular, they looked at tennis, badminton, soccer, jogging, cycling, calisthenics, swimming, and health club activities (which included treadmills, ellipticals, and weights).

The bottom line: compared to a sedentary lifestyle, playing tennis extends one's life expectancy by 9.7 years. The other sports all provided benefits too, though tennis was the clear winner. Here's a summary:

• Tennis: 9.7 years gain in life expectancy
• Badminton: 6.2 years
• Soccer: 4.7 years
• Cycling: 3.7 years
• Swimming: 3.4 years
• Jogging: 3.2 years
• Calisthenics: 3.1 years
• Health club activities: 1.5 years

The authors didn't expect tennis to do so well, as you can see in this quote:

"Surprisingly, we found that tennis players had the longest expected lifetime among the 8 different sports."

For those who don't read scientific papers regularly, I should point out that the word "surprisingly" rarely gets past the editors unless the result truly is surprising. One part of the surprise is that spending more time exercising did not correlate with the greatest benefits. In fact, the cohort of people who spent the longest time on their exercise was the health club group, who showed the smallest increase in longevity.

One possible reason for tennis, badminton, and soccer doing so well is that out of the 8 sports studied, these are the ones that require 2 or more people and involve social interaction. As the authors explain,

"Belonging to a group that meets regularly promotes a sense of support, trust, and commonality, which has been shown to contribute to a sense of well-being and improved long-term health."

Or it might be that the type of exercise you get in tennis – short bursts of activity rather than slow, steady plodding exercise – might be better for you. The authors noted that

"short repeated intervals of higher intensity exercise appear to be superior to continuous moderate intensity physical activity for improving health outcomes."

If you're still skeptical, the only other study similar to this one, a very large study from Britain published last year, came to the same conclusion: racquet sports had the greatest benefit on all-cause mortality, followed by swimming and aerobics.

So if you're not doing it already, take up tennis! It's easy to find clinics and teams at almost any level (in the U.S., that is), thanks to the thousands of local clubs and to the huge network of USTA leagues, with play ranging from beginners on up, and age groups up to 85 and even 90.

That's right, there are tennis leagues for the 90-and-over set. Maybe tennis players really do live longer.

(Caveats: this was an observational study, based on surveys of people's behavior over a 25-year time span. The scientists tried to take into account all the other variables that might affect life expectancy, but humans are complicated and surveys are never entirely reliable. We don't know that tennis, badminton, and the other sports were the cause of longer life–it might be that people who play sports are generally healthier, and that both leads to longer life and allows them to play more sports.)

Can fasting help you burn off those vacation pounds?

Vacation's over, and with it comes the end of the french fries, ice cream, and other delicious but fattening foods that are hard to resist. "I'm on vacation," we tell ourselves, "I can diet later."

Well, it's later now. How about fasting? Is that an effective way to take off the weight?

Fasting has been growing in popularity in recent years. One of the latest fads is intermittent fasting, in which you fast at regular intervals and then eat all you want in between. There's the 5-2 fast, where you eat for 5 days and fast for 2, every week. Or there's alternate-day fasting, where you eat one day and fast the next, for as long as you can. Or you can fast every day for 16 hours and get all your eating done in the other 8.

Here's the thing: eating is easy, and fasting is hard. If you're going to fast to lose weight, you probably will lose a bit, but the evidence is that most people gain the weight back fairly soon once the fasting diet is over. So fasting might provide a quick reward in terms of weight loss, but the loss will be fleeting.

Suprisingly, though, fasting may be a good idea. A recent review by Stephen Anton and colleagues, in the journal Obesity, found that intermittent fasting may come with a variety of health benefits, including reducing inflammation, improving the ratio of lean tissue to fat, improving cognitive function, preventing type 2 diabetes, and possibly even prolonging life span.

How does fasting produce these benefits? Professor Valter Longo of USC, one of the leading researchers on fasting and longevity, hypothesizes that fasting forces your body to recycle many of its immune cells, particularly white blood cells. Then your body works hard to replenish its white blood cells, essentially re-setting parts of your immune system. Longo is also the inventor of the fast-mimicking diet, where you eat a special diet for 5 days every month, one that makes your body think you're fasting even though you're getting adequate calories and nutrients. (See Alice Walton's story in Forbes for more about that.)

Another effect of fasting is a change in metabolism. As Anton's article explained:

"the key mechanism responsible for many of these beneficial effects appears to be flipping the metabolic switch." 

This happens when the body runs out of its normal fuel, glucose, and begins to burn fat, which means it's converting fat to fatty acids, which in turn produce ketones. The body then uses ketones instead of glucose.

So how much fasting do you need to flip the switch from glucose to ketones? Anton et al. write that

"The metabolic switch usually occurs between 12 and 36 hours after cessation of food consumption, depending on the liver glycogen content and on the amount of exercise during the fast."

This doesn't tell the whole story, because once the switch occurs, you need to burn ketones for some time to gain any benefits. Back in 2014, I wrote about new evidence (from Valter Longo's research) that a longer fast, such as 3 days or more provide significant long-term health benefits. Three days is a long time to fast, but Longo has said that you don't need to do it more than a few times per year.

If you do decide to try a fast, don't expect it to be easy: you're going to get really hungry, and fasting can also interfere with social obligations in an inconvenient way.

I should emphasize that the evidence isn't yet clear for any of these strategies, and there are multiple studies going on now that may provide a clearer picture. Nonetheless, despite the current fad of fasting strategies and diets, fasting really does seem to have some potential health benefits.

(A final caveat: fasting can be harmful, especially for people who have other health problems. If you’re seriously thinking of trying this, you should consult your doctor first.)