In physically trained men, performing intense exercise for 90 minutes a day over three days while maintaining normal calorie intake is linked to a higher resting metabolic rate compared to days without exercise, even when calorie intake is unchanged.

In people who train regularly, a higher resting metabolic rate is not due to long-term changes from exercise, but rather to temporary increases in energy use during and after intense activity. When those high-energy conditions are removed, the metabolic rate difference between trained and untrained individuals disappears.

Men who are physically trained have a higher resting metabolic rate than untrained men, but only when their bodies are processing a large amount of energy at that moment. This difference is not a permanent feature of training but depends on current energy use.

In physically trained men, a calorie deficit prevents any increase in resting metabolic rate, even when a lot of exercise is performed.

In trained men, resting metabolic rate increases only when both physical activity and food intake are high and balanced, not when calorie intake is higher or lower than expenditure alone.

For fit guys, a tough but short workout leads to burning more calories after exercise compared to a longer, easier workout—even if both burn the same total calories. That’s because intense workouts keep your metabolism revved up longer.