Role of Exercise

High-intensity exercise

In the app, we consider “working out” to be high-intensity aerobic training, high-intensity workouts, or heavy resistance training focused either on hypertrophy or absolute strength. This includes CrossFit, body building, powerlifting, Olympic lifting, or intense circuit training.

In this kind of training, your body burns carbohydrates as the primary fuel source. This fuel source needs to be replaced to both recover from your workouts, as well as recharge for the next training session.

You’ll see that by selecting “<90min…” or “>90min…” you’ll have more carbohydrates in your meal plan to adjust for this refueling to leave you optimally recovered and ready to smash your next workout.

Low-intensity exercise

Other types of exercise like yoga, low-intensity cardio, barre, etc, while beneficial, don’t burn fuel the same way high-intensity training does, and therefore don't require an uptick in carbohydrate consumption. Something low-intensity like a moderately paced four mile run or hour long yoga flow is fueled well by normal rest day/active rest macros.

Which is better?

Shoot for high-intensity routines a few times a week, with some recovery days of low-intensity. High-intensity aerobic exercise especially is important for heart health.

A study assigned participants to one of two groups:

The first group engaged in a program of non-aerobic exercise — basic yoga, balance training and weight training — three times a week. The other group was assigned a trainer and did moderate- to high-intensity aerobic exercise for four or more days a week.

After two years, the group doing the higher-intensity exercise saw dramatic improvements in heart health.

"We took these 50-year-old hearts and turned the clock back to 30- or 35-year-old hearts," says Dr. Ben Levine. Their hearts processed oxygen more efficiently and were notably less stiff.

"And the reason they got so much stronger and fitter," he says, "was because their hearts could now fill a lot better and pump a lot more blood during exercise."

The hearts of those engaged in less intense routines didn't change, he says.

A key part of the effective exercise regimen was interval training, Levine says — short bursts of high-intensity exercise followed by a few minutes of rest.

Until we find a miracle pill to stay young forever, exercise is pretty effective!