Exercise and Circadian Rhythms

Dr. Daniel Cavanaugh recently lectured to our neuroscience seminar about the relationship between sleep and circadian rhythms.  People often associate the two very closely together, though circadian rhythms are responsible for more than just sleep.  They control and influence a variety of bodily processes, making a regular circadian rhythm cycle vital to health.  While previous models of sleep cycles have traditionally focused on the brain as the main home of circadian rhythms (Dubowy and Sehgal), medical scientists at Northwestern have discovered circadian clocks in muscle tissue which are responsible for controlling metabolic responses and energy efficiency depending on the biological time of day.

Human patterns of exercise vary greatly in intensity, duration, and time.  Some people prefer to run as soon as they wake up, some prefer to lift weights at the end of the day, and some prefer not to do any physical activity that isn’t forced upon them.  However, a 2016 study conducted by Northwestern University of Chicago may lay the groundwork for changing the way exercise and physical activity are viewed.  The study focused on nocturnal mice and discovered that their cells were able to utilize oxygen more efficiently during their biological night, which is when they were evolved to be most active.Scientists who studied the model organism theorize that the same thing is true across all mammals.  If this is true, it could have implications for both professional athletes and people of all activity levels.  

Maximizing the body’s response to oxygen would help professionals better preform in athletic events, but could also help those with limited amounts of time capitalize on the best time of day for workouts.  With advances in biomedical technologies and the growing market for personalized health, learning when a body would be best suited to physical activity might be a valuable service.  Additionally, this new knowledge opens up the door for new potential drugs that might someday be considered on the same level as “doping” — compounds that could manipulate the circadian rhythms in muscles might give athletes an advantage in competition.  Conversely, this type of medication could also be used to even out the playing field when opposing athletes or whole teams must travel across time zones and compete during times that they might normally have been sleeping or when their muscle activity would not be optimized.

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http://www.cell.com/cell-metabolism/fulltext/S1550-4131(16)30490-9