A Time to Heal: Chronotherapy Tunes In to Body's Rhythms

Successful treatment of diseases may depend on the time of day or month that a medicine is taken or surgery performed. Asthma and arthritis pain are examples of conditions now being treated by the clock or calendar.

How our bodies marshal defenses against disease depends on many factors, such as age, gender and genetics. Recently, the role of our bodies' biological rhythms in fighting disease has come under study by some in the medical community.

Our bodies' rhythms, also known as our biological clocks, take their cue from the environment and the rhythms of the solar system that change night to day and lead one season into another. Our internal clocks are also dictated by our genetic makeup. These clocks influence how our bodies change throughout the day, affecting blood pressure, blood coagulation, blood flow, and other functions.

Some of the rhythms that affect our bodies include:

  • Ultradian, which are cycles shorter than a day (for example, the milliseconds it takes for a neuron to fire, or a 90-minute sleep cycle)


  • Circadian, which last about 24 hours (such as sleeping and waking patterns)


  • Infradian, referring to cycles longer than 24 hours (for example monthly menstruation)


  • Seasonal, such as seasonal affective disorder (SAD), which causes depression in susceptible people during the short days of winter.