Known as the ‘two-nights rule’, many athletes believe that sleeping two nights prior to race day has a positive effect on performance; more of an effect than sleeping the night before. This seems to be particularly true of longer distance runners and triathletes. Some believe this to be total nonsense while others believe it to have some credence. Is it really the sleep two nights prior to race day that matters?

Many studies have been carried out on the effect of sleep deprivation on physical performance, though not all relate to athletic performance or to the two-nights rule. Some of these studies explain how this belief may have come about. There are those that believe the effect to be psychological while others suggest that there might be some metabolic truth in the ‘rule.’

Avoiding Sleep Deficiency

Athletes who don’t believe in the two-nights rule should do their best to ensure they get a good night’s sleep. It’s a myth that a hot milky drink at night will help. There is insufficient tryptophan in milk to make much difference. There are dangerous side effects to taking tryptophan supplements to generate the sleep-inducing serotonin.  

Far better is to eat turkey, kiwi fruit and/or almonds.  Turkey contains natural tryptophan, a precursor of the sleep-inducing serotonin.  Kiwi fruit contains serotonin and antioxidants that reduce inflammation, and almonds which are also a source of serotonin plus magnesium which can help those with insomnia get sleep. Wash it all down with chamomile tea that also contains antioxidants including the sleep-inducing apigenin.

In addition to that, make sure you sleep on a comfortable mattress. You don’t need an expensive mattress to help you sleep: there are plenty excellent budget mattresses available at very affordable prices. Many people with sleep issues find that they can solve their problem simply by changing their mattress. Also you may not need a proper bed for a better sleep, rather a good floor mattress is enough to have a good night sleep.

Metabolic Explanation of the ‘Two-Nights Rule’

The Lancet summarized an October 1999 study by Spiegel, Leproult and Van Cauter, showing that sleep debt had a negative effect on carbohydrate metabolism.  It can be argued that poor conversion of glucose to energy is sure to have an effect on athletic performance. Thyrotropin concentrations were also lower, resulting in reduced levels of thyroxine, responsible for oxygen consumption and consequently all cell and tissue metabolism.

Glucose is used for energy at the time of demand: during the race. A lack of sleep the night before the race should therefore affect performance.  It has yet to be established, however, that one night of poor or no sleep will cause sufficient deficiencies as to affect race performance.

One Night’s Sleep Deficiency: Athletic Performance and Reaction Time

During sleep, your body builds muscle tissue and repairs damaged muscle. This is an efficient process in a trained athlete. However, is it necessary the night before the race? Probably not! In a Runner’s World article some elite marathon runners answer questions about how they sleep. Many find it difficult to sleep, or can’t sleep, but it does not appear to affect their performance.

While a night without sleep may have little influence on athletic performance, it does have an influence on reaction time. A study carried out by the Asian Journal of Sports Medicine showed that while sleep deprivation had no effect on anaerobic power, it did slow down reaction time. It would, therefore, affect sprinters more than longer distance runners due to the importance of a quick start to the former.

Effect of Aerobic and Anaerobic Training

The purpose of training is to build muscle and condition your body to handle the needs of a race. Aerobic exercise makes your heart become more efficient and more able to meet the increased oxygen demand of a race. It also improves endurance and stamina. Anaerobic exercise builds muscle mass, improves your VO2 Max, builds your energy reserves and enables you to put on a sudden sprint when needed.

You are not going to lose these benefits by missing a few hours of sleep. A well-trained athlete is not going to lose performance after just one night of lost sleep. Many studies have shown this, but two nights or more without sleep can have a significant negative effect.

Believers in the Two-Nights Rule Worry Less

Another explanation is that athletes who believe in the two-nights rule worry less about getting good sleep the night before their race. Having slept well the previous night, they are not so concerned about sleep the night before their event. With less worry and more confidence in their upcoming performance, such athletes may run with confidence knowing they slept two nights before.

A lack of sleep on the last night before your race does not appear to significantly affect your performance – if at all.  Good training, sleep two nights prior to race day and pre-race nerves likely have more to do with how well or badly athletes perform on race day; more so than not sleeping well.