Exercising will protect you from feeling sick

AP

People who exercise more get sick less.

That's according to Jawbone, the company that makes wearable bands that measure activity and track sleep.

Jawbone's data scientists analyzed activities and feedback from tens of thousands of people that use its products to learn about the relationship between exercise behaviors and how people feel health-wise.

Since people can write comments about how they're feeling in Jawbone's UP app, which is used in tandem with the company's fitness trackers, Jawbone's data science team looked for words associated with the flu, like "sick," "viral," "Tylenol," and, of course, "flu," among others.

This allowed the Jawbone team to come up with what it calls a "sickness likelihood score."

The data scientists found that in general, people with a higher body mass index (BMI) were more likely to report symptoms of being sick. That is, overweight people reported symptoms of being sick more frequently than those with lower BMIs.

One exception in the group, however, were underweight people between the ages of 55 and 64, who were actually most likely to get sick in that age group.

Jawbone also found that within the group of Jawbone app users, people who were more active were less likely to get sick.

Men between the ages of 25 and 44 (who have "normal" BMIs) that walked more than 14,000 steps each day were four times less likely to get sick compared to those who walk fewer than 4,000 steps daily.

One important caveat with this data: Jawbone is studying a self-selecting group, which means it's difficult to draw meaningful conclusions that apply to a broader population. The symptoms are also self-reported by users, so the diagnosis of "sick" is highly subjective (the threshold for "I need Tylenol" is not consistent, for example).

It's also impossible to know whether something like the association between high BMI and higher likelihood of sickness is because higher BMI leads to sickness, because frequent sickness leads to higher BMI, or because of some unrelated factor that wasn't being measured. 

That said, some of what Jawbone found in this particular instance is backed up by peer-reviewed studies. A study published in 2012 in the journal PLOS ONE found that "moderate to high amounts of physical activity may be associated with a reduced risk of influenza" for people under the age of 65.