Muscles Have Internal Clock
Northwestern Medicine scientists confirmed that all cells in the body, including those in muscle, contain a clock that regulates how cells adapt to changes in the environment and activity across the 24-hour day. This finding is consistent with the thousands-year-old Chinese Medicine theory regarding the flow of Qi (vital force, energy) in the body throughout the day.
Researchers at Northwestern Medicine found that muscles are more efficient during an organism's normal waking hours. "The capacity for a cell to perform its most important functions, to contract, will vary according to the time of day. The muscle clocks control the metabolic response by interacting with proteins called HIFs that change metabolism when oxygen concentrations get too low in order to allow muscle cells to continue to make energy," says Dr. Joseph Bass. This suggests that humans may be able to respond better to exercise during the daytime and that better exercise capacity may be tied to specific times of day. Nowadays, lots of people hit the gym after work in the evening hours further exhausting their energy instead of reducing their energy output later in the day, thus depleting their overall energy and wellness.
It may be wise to get up early and exercise in the morning and conserve and recharge one's energy through relaxing with a massage, acupressure or enjoying your friends' company in the evening.
The research has implications beyond muscle cells because oxygen response is important in all cells. In particular, the deprivation of oxygen is a key factor in many diseases such as heart attacks or cancers, where cancer cells grow due to oxygen depletion. Soon, we may learn more about how the internal clock affects our muscles, metabolism or endocrine system. In meanwhile, the meridian body clock (see the illustration above) may serve as a useful guide to organizing your daily activities and reminding yourself that for everything there is right time.
Source: Clara Bien Peek, Daniel C. Levine, Jonathan Cedernaes, Akihiko Taguchi, Yumiko Kobayashi, Stacy J. Tsai, Nicolle A. Bonar, Maureen R. McNulty, Kathryn Moynihan Ramsey, Joseph Bass. Circadian Clock Interaction with HIF1α Mediates Oxygenic Metabolism and Anaerobic Glycolysis in Skeletal Muscle. Cell Metabolism, 2016; DOI: 10.1016/j.cmet.2016.09.010.