Study Hints How Exercise May Lead to Weight Gain

Sessions of intense exercise can reduce subsequent physical activity and body temperature, potentially contributing to weight gain in animal models.

There is no debating the benefits of exercise for overall human health. Regular physical activity reduces the risk of developing heart disease, cancer, type 2 diabetes, and obesity.

However, when it comes to weight loss, the benefits of exercising may be more modest.

While physical activity supports weight loss by improving metabolism and regulating mood and sleep, experts emphasize that exercise must be combined with a healthy diet.

A new study in mice by researchers from the University of Tsukuba, Japan, suggests that high-intensity exercise may lead to weight gain.

The researchers divided the mice into three groups: high-intensity exercise, moderate-intensity exercise, and rest. They were monitored for physical activity and core body temperature, which serve as an index of heat production before and after exercise.

Mice who engaged in high-intensity exercise had their physical activity and core body temperature significantly decrease after exercise, although their food intake did not change.

Furthermore, they experienced a disruption in the synchrony between physical activity and body temperature. The study confirmed the correlation that relatively low levels of corticosterone, the stress hormone, during wake times were associated with less physical activity.

The authors concluded, “This study highlighted the importance of considering not only the calories burned during exercise but also the subsequent activity levels and circadian rhythm when designing exercise regimens for effective weight loss.”

However, since the study was conducted in mice, the findings may not necessarily apply to humans. Moreover, weight loss is a complex combination of multiple factors and encompasses much more than physical activity.

Exercising can also lead to short-term weight gain due to increased muscle mass. Therefore, the findings should not discourage people from exercising, as its benefits are well-established.

How much should I exercise?

Every week, adults should do at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic physical activity, according to the Physical Activity Guidelines for Americans.

Some examples of moderate-intensity activities are the following:

• Brisk walking at 2.5 miles per hour or faster
• Recreational swimming
• Cycling slower than 10 miles per hour on level terrain
• Tennis (doubles)
• Active forms of yoga, such as Vinyasa or power yoga
• General yard work and home repair work

A person engaged in vigorous-intensity activity can’t say more than a few words without stopping for a breath. This type of activity includes:

• Jogging or running
• Swimming laps
• Tennis (singles)
• Vigorous dancing
• Cycling faster than 10 miles per hour
• Heavy yard work, such as digging or shoveling
• High-intensity interval training (HIIT)

Adults should also do muscle-strengthening activities involving all major muscle groups two or more days a week.

Exercise is essential for staying healthy and can support weight loss. However, low body weight does not automatically indicate good health.