Every time you engage in physical activity, you put a certain amount of stress on your body. In aerobic activities, this means working out to a point where you begin to break a sweat. This usually happens when you get your heart up to 70 percent of its maximum limit for a reasonable period of time. Once this occurs, things are happening at the molecular level; in particular, you are making your cells more responsive to taking up blood glucose, thereby decreasing the amount of insulin needed to be secreted by the pancreas. If you are overweight or out of shape, then it won’t take you very long to begin to increase your core temperature and break into a sweat. That’s a good point to stop exercising that day. With time and consistent exercise, you will have to work out longer or with more intensity to reach the same point of exertion.

Strength training works very differently from aerobic exercise to reduce insulin levels. By building more muscle mass, your body will have an easier time extracting glucose from the bloodstream and your need for insulin will drop. Regardless of your form of exercise (aerobic versus strength), the long-term outcome is the same: reduction of excess insulin.

However, there are other hormonal changes that take place with strength training that do not occur with aerobic training. When you exercise your muscles to exhaustion, a certain level of trauma occurs. This triggers a pro-inflammatory response to treat the micro-tears in your muscles.

If the pro-inflammatory response is not too severe, there will be a corresponding anti-inflammatory response to repair the muscle damage and increase muscle strength for the next bout of exercise. Part of that anti-inflammatory response is the release of growth hormone from the pituitary gland to rebuild the damaged tissue and make it stronger. This is why strength athletes are much more muscular than endurance athletes, although both have low levels of fasting insulin.

Moderate strength training should provide you with just enough micro-trauma to allow you to sufficiently recover from your workouts to repair and rebuild your muscles before your next strength workout. As you age, the time for this repair process increases. This is why young athletes can do intense two-a-day workouts, whereas older athletes should do moderate strength training every other day. The amount of recovery time ultimately depends on your innate anti-inflammatory responses, which can be enhanced by following the Zone Wellness Pyramid. However, no matter how good your dietary program, excessive exercise increases inflammation to such an extent that it overwhelms the body’s ability to produce sufficient levels of anti-inflammatory eicosanoids needed for recovery. The end result is you’re still sore and weak from your last workout on the day of your next workout.

The most important thing is to listen to your body. If it’s still sore from your last workout when you’re about to begin your next one, you’ve probably pushed it too hard and your body is still churning our inflammatory mediators. Rest some more, and cut back a bit on your next workout.