Spring is around the corner, but many people still fight the battle of sneezing, coughs and congestion which is related to the common cold. It is normal to suffer two to three times a year from respiratory infections. Viral infection causes an inflammation of the upper respiratory tract that is normally defined as the “cold.” Furthermore, the U.S. Centers for Disease Control and Prevention estimates that 425 million colds and flus occur in a year.

Not everybody is equally affected in catching a cold. There are several factors that reduce the immune system and its function, such as old age, cigarette smoking, stress, poor nutrition, few hours of sleep and excessive exercising.

However, moderate exercise helps to boost the immune system and it is estimated that 20-30 percent of people who exercise regularly have fewer colds than their sedentary peers. In fact, the American College of Sports Medicine reported that a survey revealed that 61 percent of 700 recreational runners reported fewer colds since beginning to run, while only four percent reported an increase. In addition, another ACSM survey stated that 90 percent of long-term runners reported that “they rarely get sick”.

Moderate exercising, such as brisk walking for 30 to 40 minutes daily, will boost the immune system in the short, as well as long, term. During a walk the blood flow increases and the immune system produces more macrophages (white blood cells) in the blood that attack bacteria. Furthermore, during exercise the lungs work harder by breathing more often and also more deeply which aids in the elimination of airborne bacteria, viruses and other cancer causing substances.

Waste elimination due to increased urination and sweat is also part of increasing the defense mechanism that comes from exercise. The increase in body heat will hinder the growth of bacteria, which will reduce the risk of getting sick.

On the contrary, too high intensity training will reduce the immune system for a brief period of time. Marathon runners or triathletes experience a 72-hour “open window” in which they are more susceptible to illness than people who moderately exercise. In order to avoid this to occur experts recommend enough rest days to recover between training days and after competition.

Most experts agree that it is safe to exercise if there is no fever accompanied with symptoms of the common cold, as long as the intensity is kept low. A cold that is associated with body aches, fever, chest congestion and tiredness requires about two weeks of rest, which will allow the body the necessary time to focus on healing versus performing.

Regular exercise is beneficial for more than preventing diseases such as heart disease or osteoporosis. Moderate intensity will give your immune system the extra strength to fight off bacteria and viruses that are associated with the common cold. Dress in layers and take a half-hour walk daily. The spring sun and fresh air will have a positive effect on your body, as well as you psychological well being, every time you step outside for a walk.