Written by Dr Philo Saunders

Most of us don’t have the luxury of revolving our lives around running – we fit it in when we can. But, is there an optimal time to train?

A variety of factors need to be taken into consideration when determining the best time to train during the day. These factors include your work/study schedule, type of session to be undertaken, whether you run once or twice a day, previous training/race stress, temperature and daylight, as well as upcoming competition conditions. Another important factor influencing training time is the body’s circadian rhythm. Circadian rhythm is the term used to describe the daily cycle of physiological, biochemical and behavioural processes in a living organism. These processes are synchronised to a solar (24 hour) day. The body clock, through transmissions from the brain, controls temperature regulation, hormone release, hunger, sleep and waking (2). The majority of components of sports performance, for example, flexibility, muscle strength and short term high power output, vary with time of day in a sinusoidal manner being lowest in the early morning and peaking in the early evening close to the daily maximum in body temperature (1). The benefits and disadvantages of training at different times of the day will be discussed, as well as advice as to which types of training are more appropriate at particular times of the day for maximum training gain.

Morning
Training first thing in the morning is essential if training twice a day and can either be an easy jog or the main run/session on double training days. If you have to go really early to fit in with work/study, it is advised to do the easy run in the morning before breakfast. If you have more time in the morning, the main run or session can be completed, especially if you are busy during the day and may be tired for an evening session. For an interval type session, it is usually beneficial to get out of bed at least 30 minutes before warming up for the session to allow your body to wake up and for the muscles to become activated prior to intense exercise. Remember that body temperature is at its lowest point in the morning. For optimal performance in sessions body temperature needs to be elevated, which can be achieved by getting up long enough before the session and completing a sufficient warm up. Intake of food and drink is also advisable for a session or long run to ensure you have enough energy and hydration for the session. For single run days, morning runs are good as long as you have not trained too hard the evening before. In this case, it is probably better to go at noon or in the evening to give your body more recovery, especially if the run is at a high intensity.

Training in the morning can be perfect for many reasons, but does take a strong commitment.
Noon
Lunchtime runs or sessions are great during the winter in colder climates when training once a day, as recovery from the previous day’s training is maximised. It can also be the best part of the day to train temperature wise. Longer runs or sessions in the summer months can be important for acclimation for hot weather competitions, although as mentioned in previous issues, care must be taken to maintain hydration and glycogen levels, avoid sunburn and incorporate recovery strategies after training in hot conditions. There is some evidence that performance variables such as muscular strength experience a lull in the middle of the day, which may be worth considering for important sessions. Lunchtime training can also be great to break up a long work day or avoid getting up really early or training late in the evening when tired from work.
Lunchtime training can be great to break up a long work day!

Night
For those who work/study during the week and have early starts, main sessions are probably best done in the evening. The natural circadian rhythm also sees most body functions important to running performance at their peak early in the evening. This means for those really high quality sessions, the evening may be the best time to train. Longer runs can be done in the evening if you have trained hard the night before to allow maximal recovery time between sessions. Evening sessions usually allow a bit of respite in summer to avoid excessive heat stress while training. Evening sessions can sometimes be compromised if you are really busy during the day but can be better than going very early in the morning to avoid dark, cold training sessions when the body is not ready to train hard.

The body’s natural circadian rhythm means running performance is at its peak early in the evening.

Conclusion
This article has summarised some important points when planning your training program and deciding when in the day to train. Although the body functions best in the early evening and worst in the early morning, other factors such as work, previous training, number of sessions required for a specific day, daylight and temperature need to be considered when working out your training schedule. Most runners can train well at all times of the day with sufficient preparation. Working in with your training group, specifically preparing for the time of your major up-coming race or other commitments will usually decide the time of day you train during a training week.

References

  1. Atkinson G, and Reilly T. Circadian variation in sports performance. Sports Med 21: 292-312, 1996.
  2. Reilly T. Human circadian rhythms and exercise. Crit Rev Biomed Eng 18: 165-180, 1990.