Reading a SPORTS (Science Periodical on Research and Technology in Sport) pamplete title "Timing Travel and Athletic Performance (Oct 1984) written by Charles M Winget PhD who explains how performance is affected by Jet-Lag when involved in International Competitions.
Mr. Winget, who died in July 2013, was involved with NASA's biomedical research in Space travel.(Biomedical Research Div of NASA ) and their research on speed with Astronauts health.
At the end of Mr. Winget article which was published by the Coaching Association of Canada in October 1984; we find the following advice.
"As general advice "For the athlete who has not pre-adapted to destination time clues, if possible , avoid important athletic competitions in the morning hours during the initial days after long eastbound flights and last afternoon hours after a west bound flight."
Your internal clock, called a circadian clock, cycles about every 24 hours and "Circadian rhythm disorders", also known as sleep-wake cycle disorders, are problems that occur when your body's internal clock, which tells you when it's time to sleep or to wake, is out of sync with your environment. (US NHLBI)
There are several aspect of this science involved in a Coach's intervention in the performance of their athletics. From schedule practice after a competition with the intention to allow for a stressful competition to be surpressed and the athletic rest; to the development of Practice and Preparation to allow the athletic to reach his Performance Peak at the actual time of competition. Or as per the Jet-lag research the influence on a athletic at Peak Performance due to lack of successful recovery.
The Canadian Coaching Association article by Charles M Winget stated the following
"Jet lag, the disruption of circadian (daily) rhythms, is a recognized air travel syndrome that athletes, tourists and business executives alike must confront when flying across more than a few time zones.
The most familiar daily rhythm is sleep and wakefulness. But the body has many biological clocks, some daily, some on other schedules. Most biological functions are rhythmic in character, increasing and decreasing at constant rates. Under normal conditions, all of these rhythms operate in specific phase relationships to one another. The smooth functioning of the body , as a system depending on the maintenance of these timing relationships. So the physiological rhythms noticeably lower at night are heart rate, blood pressure and body temperature. Kidney functions is also low at night but high during the day. Metabolism is highest at noon. Adrenal rhythms are highest during the early sleeping hours and during peaks in the last evenings."
"Disturbing physiological rhythm relationships, jet lag can have far-reaching effects on performance. These effects can range from fatigue and irritability to serious sleep disorders, headache, and acute intestinal upset. The particular symptoms experienced and their severity vary from individual to individual. If you add these internal troubles to the external stress of facing a tough opponent and the stage is set for ineffective performance"
"Thus the competitive athlete who understands circadian
(from the Latin circa and dien - about a day) rhythms will be able to perform more effectively. The coach will also be in a better position to improve team performance because relatively small, individual decrements in performance can add up to larger team performance decrements."
Further, after a short history on jet lag the articles states
"The very speed of travel is, however, accompanied by exposure to certain transent distrubances in physiological functions. These changes occur whenever we quickly move from the time zone in which we normally live to a new time zone where local time is several hours different. Thus , we experience disorientation in time when we fly west or east but no disorientation in flying north or south."
"The symptoms of Jet lag, usually felt soon after disembarking from a long Jet flight are disorientation, confusion, distortion of the senses of time and distance, fatigue, upset stomach, constipation or diarrhea, decrements of physical and mental efficiency, and disturbances in sleep habits. The nature of this malady is actually a state of disarray in the body's physiological cycles or biological clocks. Body cycles either out of synchrony with each other or with environmental cycles are in a condition scientist call dysrhythmia. The symptoms of dysrhythmia, following transmeridian flights, are commonly referred to as jet lag. The body cannot reset its biological clock with the same ease that we adjust our watches to a new time zone. In fact, it has been suggested the peak decline in psychomotor performance to to jet lag alone corresponds in young humans to the decline in performance which results from the 0.1 percent blood level."
Virtually unknown 30 years ago dysrhythmia today is perhaps the most frequently experienced peril of the jet travelling athlete." The article gave an example of "a Boston based runner who planned to go to a race in Hawaii", but was called to Paris on Business. "After 10 days in Europe, he returnedafter eating breakfast in Paris, With another breakfast in New York (Paris time 5pm), then Lunch in San Francisco with friends; he then, the next day, flew to Hawaii. Only to find that he was tired, irritable, mentally disoriented and suffering acute indigestion"
"Biological or circadian rhythms are not to be confused with the discredited, so called biorhythms of 23-days physical cycle, a 28 day emotional cycle and a 33 day intellectual cycle"
Dr. Daniel C Holley, professor of physiology at San Jose State University reviewed with his colleagues the literature dealing with internal and external factors which induce modification of performance rhythms. Among the factors investigated were motivation and sleep deprivation. Motivation or extra effort is able to improve physical performance for a limited time. Extended sleep (e.g. 12 hours) following a long jet flight can make up for sleep lost. However, a night's rest is not enough to bring the physiologic clock into phase with local time. This adjustment is gradual and usually takes one day for each time zone crossed."
After discussion the sleeping problems like "Micro-sleep episodes" which can cause car accidents because of short micro second falling asleep; Dr. Winget explains how the electroencephalogram brain waves frequency change (alpha waves) and their micro voltage (delta waves). Dr Winget went on to explain how during sleep, the body shuts down all muscles while activating organs like kidneys. This was summized as
" It is important for the athlete to keep in mind the significance of the circadian variation in circulatory system dynamics, which influences delivery of oxygen, glucose and hormones to the various organs , including the brain."
"There are circadian rhythms in a variety of neuromuscular functions which affect athletic performance. These include reaction time, grip strength and Achilles tendon reflex, elbow flexion strength, nerve condition velocity and resting forearm blood flow.
The Achilles tendon reflex is highly correlated with a person's metabolic state and thus is an indication of the general state of activity." The function state of skeletal muscle is an important measure of the overall strength and efficiency of a trained athlete during the course of a day. Maximal voluntary contractions have been observed to change with a circadian pattern. Unfortunately, the physiological measurement of maximal strength is almost complicated by psychological factors such as motivation and emotional state."
In Conclusion - " An athlete's hours of peak performance on tasks requiring muscle coordination, will coincide with the time of highest body temperature in the late afternoon and early evening" (time zone corrected). The worst performance period for both males and females will occur at the time of lowest body temperature in the early morning."
"Concerning the Body's cycle and performance, the presence of circadian rhythm in performance has been well documented. In general, the range of circadian oscillation is greatest in physiological tasks than for psychological tasks. However, the circadian rhythm is a major source of variability in performance (e.g. 10-30 percent of the 24-hour mean) and the range of oscillation (amplitude) increases with increasing task complexity."
"Research has been conducted to determine the specific effects of Jet lag and circadian rhythmicity on athletic performance and significant results have been found . The findings of Keneko suggest athletic events depends upon short duration physical power (e.g. weightlifting and some gymnastics events) are significant affected by the timing (i.e. the circadian rhythm) of blood flow to the muscle. Any disruption of this timing by Jet lag or desynchronosis would subsequently affect an athlete's performance.
Some strange facts are also explained in the article like "Significant performance declines are found only in the eastbound Direction" or "The athlete should reset his or her physiological clock to be in correct environmental timing with the place of destination".
The International "Competition" Athletic's Coach there is much research published such as "The role of circadian rhythm on sports performance, hormonal regulation, immune system function, and injury prevention in athletes" (Heliyon, 9 2023 e19636) of which the Objectives is defined as: "This study was a narrative review of the importance of circadian rhythm (CR), describes the underlying mechanisms of CR in sports performance".
For the Profession athletics Medical Staff the reader might find interest from. Chronobiology International which writes on recent research in it Online Journal. which suggests:
" Strength coaches and medical staff of professional teams should strongly consider actigraphy as a practical and powerful tool to monitor RARs,( rest-activity circadian rhythms), sleep behavior, and the activity levels of their athletes; highlighting potential circadian disruptions through actigraphy could be helpful to prevent musculoskeletal (involving both musculature and skeleton) injuries".