Know this: Although poor sleep can impact cancer risk through a number of obvious mechanisms, scientists speculate that its drain on the immune system (your body’s anti-cancer and anti-infection system) is likely the most significant factor.

A stunning (headline news) report from the January issue of the Archives of Internal Medicine hammered home how essential sleep is beneficial for optimal immune function.

In a nutshell: Study subjects who slept fewer than seven hours a night were almost three times more likely to catch a cold than those who slumbered for eight hours or more. Perhaps even more striking, study subjects with poorer sleep efficiency, 92% or less, were 5.5 times more likely to get sick! (Sleep efficiency is the percentage of time spent in bed actually sleeping.)

Based on all the science I have reviewed, the two most powerful things you can do to maintain robust immunity are getting optimal sleep and taking part in regular daily physical activity. Incidentally, I firmly believe that getting optimal sleep is impossible without a certain threshold level of daily physical activity.

Dr. Ann Kulze is founder and CEO of Just Wellness and has a knack for breaking down the science of healthy eating and living into simple and easily digestible messages. She has been featured on “Dr. Oz,” “Oprah and Friends,” WebMD and U.S. News & World Report. Alabama NewsCenter is publishing advice from Dr. Ann.