The ability to sustain a high rate of energy burn for a prolonged period of time may help ward off cancer. Last fall, an international group of exercise oncologists published a major review of the literature on exercise and cancer. The news was good, if somewhat unsurprising. Regular exercise lowers your risk of developing a long list of cancers, in some cases by 10 to 25 percent; and if you do get cancer, exercise enhances the quality and possibly the expected length of your life.
But there was one notable omission from the review. The experts weren’t entirely sure how or why exercise has such a powerful effect on cancer cells. There are plenty of theories involving things like hormone levels, blood sugar, chronic inflammation, and oxidative stress, but no one has put all the pieces together.
It’s in that context that an opinion piece in the journal Trends in Cancer recently appeared, from a group led by Peter Biro of Deakin University in Australia. Biro and his colleagues propose a new theory in which the link between exercise and cancer is explained by what they call “energetic capacity.” In short, fit people are able to ramp up and sustain high levels of energy consumption, which gives them the ability to mount a more robust immune response when cancer cells attack and also helps them to withstand the energy-sapping effects of tumors that do get a foothold.
This is a hard theory to test experimentally, but the researchers explore four predictions that follow from their idea.
We All Have a Different Energetic Capacity
This may seem like a no-brainer, but it’s worth unpacking what they mean by energetic capacity. We get our energy from food, so in theory you might think that if it takes extra calories to fight off cancer, you can just down a few more sandwiches. But as a recent paper by Herman Pontzer and John Speakman argued, there are limits to how much energy our bodies can process. You simply can’t burn 10,000 calories a day, no matter how much you try to eat.
It’s also clear that some people can burn more energy than others, and that these differences are in part heritable.That means that if you’re in a situation where your body needs all the energy it can get, and it needs to sustain this output for days or weeks, some people will be able to handle this challenge better than others.
Read more at: https://www.outsideonline.com