BOOST your Immunity!

Regular Moderate Exercise Boosts Immunity
However, there are some things that seem to protect us from picking up colds. One of those things appears to be moderate, consistent exercise. More and more research is finding a link between moderate, regular exercise and a strong immune system.

Early studies reported that recreational exercisers reported fewer colds once they began running. Moderate exercise has been linked to a positive immune system response and a temporary boost in the production of macrophages, the cells that attack bacteria. It is believed that regular, consistent exercise can lead to substantial benefits in immune system health over the long-term.

More recent studies have shown that there are physiological changes in the immune system as a response to exercise. During moderate exercise immune cells circulate through the body more quickly and are better able to kill bacteria and viruses. After exercise ends, the immune system generally returns to normal within a few hours, but consistent, regular exercise seems to make these changes a bit more long-lasting.

According to professor David Nieman, Dr. PH., of Appalachian State University, when moderate exercise is repeated on a near-daily basis there is a cumulative effect that leads to a long-term immune response. His research showed that those who walk at 70-75 percent of their VO2 Max for 40 minutes per day had half as many sick days due to colds or sore throats as those who don't exercise.

Too Much Exercise May Decrease Immunity
However, there is also evidence that too much intense exercise can reduce immunity. This research is showing that more than 90 minutes of high-intensity endurance exercise can make athletes susceptible to illness for up to 72 hours after the exercise session. This is important information for those who compete in longer events such as marathons or triathlons.

Intense exercise seems to cause a temporary decrease in immune system function. Research has found that during intense physical exertion, the body produces certain hormones that temporarily lower immunity.

Cortisol and adrenaline, known as the stress hormones, raise blood pressure and cholesterol levels and suppress the immune system. This effect has been linked to the increased susceptibility to infection in endurance athletes after extreme exercise (such as marathon running or Ironman-distance triathlon training).

If you are training for ultra-endurance events, a key component of your training should be including enough rest and recovery days to allow your body (immune system) to recover. If you are feeling run-down or have other symptoms of overtraining syndrome --such as increased resting heart rate, slower recovery heart rate, irritability or general heaviness and fatigue -- you may need to tone down your workouts as well.

If you are already ill, you should be careful about exercising too intensely. Your immune system is already taxed by fighting your infection, and additional stress could undermine your recovery. In general, if you have mild cold symptoms and no fever, light or moderate exercise may help you feel a bit better and actually boost your immune system. Intense exercise will only make things worse and likely extend your illness.