Exercising when sick – a smart move? Published Dec. 29, 2014 Health.mil WASHINGTON -- Is it safe to exercise when I'm sick? This is a common question, especially from people who have strict workout schedules and aren't likely to let the sniffles get in the way of their physical fitness. Benefits of exercise include weight control, improved mood, more energy, and better sleep. What's more, just 30 minutes of regular exercise three or four times per week can boost your immune system and improve overall health, helping to keep those colds at bay. Moderate exercise while you're sick can be safe and in certain cases may actually improve symptoms (such as relieving congestion and increasing energy). But first you need to determine "how sick is sick." You can figure this out by using the "neck rule." If you have symptoms above the neck--including sore throat, nasal congestion, sneezing, or watery eyes--then moderate workouts can continue. If symptoms are below the neck--including cough, fever, fatigue, or body aches--then rest is in order until the symptoms are gone. You can also use your temperature to determine whether exercising is okay. If you have a temperature of 101°F or higher, moderate or vigorous exercise is not wise because of the risk of heat-related illnesses and dehydration. Ultimately, the decision to exercise when you're sick is up to you. If you're too weak and fatigued to get out of bed, exercising may not be the best thing to do at that time. However, if you have symptoms of a cold and your temperature is below 101°F, light to moderate exercise may be beneficial. You should consider seeing a doctor if your symptoms don't improve or get worse.