Published in the Journal of Sports Sciences, a new study from Loughborough University team in England found that intense exercise can cause sleep disturbance, as illustrated by the effects of two episodes of intense training lasting nine days on 13 well-trained cyclists.
Researcher S.C Killer and her colleagues discovered that as little as nine days packed with intense exercise resulted in progressive and significant decline in sleep quality, and witnessed worsening moods and ability for more intense exercise in the athletes during the study run.
The researchers reported that sleep efficiency was greatly reduced during the intensified training period, and they noted that the amount of the times the athletes woke up during the night also significantly increase.
The participants of the study had shifts in mood as well, such as tension, greater stress symptoms, anger, fatigue, depression and confusion. Although data showed an increased time spent in bed during times of intense exercise, the extra time in bed did not result in any more actual sleep.
A high-carb diet was found to minimize some effects of intense exercise, while the moderate-carb diet led to a higher sleep rate but possibly showed greater recovery requirement and higher fatigue levels.
The research team noted that a successful training cycle continues to a serious fatigue state, followed by rest. Such training prompts positive adaptations as well as improved performance.
However, the team warned that if intense exercise is not followed by enough rest, overreaching may occur.
The researchers also encourage all sports coaches to support and permit enough rest time in the training of their athletes, including plenty of naps.
Scientists still have to agree on the optimum amount of sleep each night for both non-athletes and athletes, but a recent study demonstrated that sleeping for more than nine hours each night and sitting for extended amounts of time can actually shorten a person’s life.
And when too little exercise is thrown in, it creates a “triple whammy” effect.