It’s far better to exercise three times daily when you have time 20 to 40 minutes than enduring 1 1/2 hour of strenous activity and here is “why?” There are somethings that seem to protect us from catching colds and flu. During moderate exercise immune cells circulate through your body more quickly, thereby, moderate exercise has been linked to a positive immune system response and temporary boost in the production of macrophages, the cells that attack bacteria.
According to professor Dr. David Nieman, PHD., of Applachian State when moderate exercise is repeated on a routine daily basis. There is a cumulative effect leading to a long term immune response and his research showed those whom walk at 70 – 75 percent of their VO2 Max for 40 minutes per day. Ended up having half as many sick days…. due to colds or sore throats as those who don’t exercise.
However, evidence supports intense exercise for more than 90 minutes, can make athletes susceptible to illness… up to 72 hours after high intensity endurance training. Research has found during intense physical exertion the body produces certain hormones that temporarily lowers immunity. Cortisol and adrenaline, known as stress hormones; raises blood pressure, cholesterol levels and supresses the immune system.
It’s not only physical stress that increases the release of cortisol and adrenaline. Psychological stress can also impair immunity and lead to an increase of colds and flu infections. Researchers at Ohio State followed people who had the stress of caring for a loved – one with Alzheimer’s and found they experienced twice as many colds as non – caregivers.