Sleeping with Dragons…
The fact that sleep is important, not only for athletic performance but also optimal functioning of non-athletes in daily life, is well documented and encouraged. Despite this, scientific research and data that advises on the management of sleep deprivation is still fairly scant. In writing this article I have made every effort to source valid, scientific information and provide viable sleep strategy options, but ultimately each team must make their own choices. Selection of pre- and during-race protocols, as well as the use of nutrition and supplements to improve alertness, will all be influenced by individual preferences as well as environmental conditions during the race, and special consideration should be given to safety on the mountain at all times.
Photo Credit: Nicolette Griffioen
Let’s start with a pre-race sleep discussion because regardless of your team’s DGT Run time goal, everyone is going to experience sleep deprivation to some degree during the event. In light of this, it is probably a good idea to prepare in some way and there are two, polar-opposite strategies which can both actually be applied ahead of the race.
The first and better documented concept is known as “sleep banking” or sleep extension. This involves sleeping more than usual in the lead up to expected sleep deprivation, in order to delay the onset of fatigue and effects of sleep deprivation. This strategy was first studied many years ago in populations of shift workers - specifically sailors, long-haul pilots and medical personnel - and results showed that banking of sleep improved performance and prolonged cognitive function. A variety of applications of this method may be effective, including just one week of increased daily sleep prior to your event. One study involving cyclists and triathletes showed better endurance performance after three consecutive nights of sleep extension from an average of 6.8 hours to 8.4 hours of sleep per night. Another study involved scheduling a window of 9 to 10 hours for sleep in collegiate basketball players. Applied for 5-7 weeks, the athletes improved reaction times, sprint times, mood and accuracy. But the simple take-home message here is that going into your DGT with sleep credit as opposed to sleep debt can only serve you well. So make the effort in October to bank some extra shut-eye!
A more novel idea in preparation for a period of little sleep is “sleep deprivation training.” While the Italians have apparently been applying this technique before the 330 km Tor des Geants for a while, only one scientific study involving a single participant is currently known. In this study a male ultra runner underwent a 6-week sleep deprivation training program, consisting of 1 night’s full sleep deprivation every Sunday while maintaining his regular physical training program. Before and after the 6 weeks of training the participant performed 5 consecutive days of daily, 2-hour, constant-pace running with sleep deprivation on the first and third night. This served as a pre- and post-deprivation training comparison. Both psychological and physiological responses were measured during this 5 day period. Results showed that the training was well tolerated by the athlete and he experienced less “sleepiness” and lower perceived mental effort during sleep deprivation after the 6 week program.
While a lot more research obviously needs to be done in this field to determine whether or not physiological adaptations occur, and to quantify the detrimental effects of sleep deprivation on performance, there may still be validity in training the mental approach. Just reducing perceived effort, knowing your body’s response to sleep deprivation and being comfortable and confident in managing it is beneficial. So while I don’t think 6 sleepless nights is necessary in the 6 weeks before DGT Run, consider doing at least one and maybe squeeze in a second a few weeks out from the race!
This brings me to the during-race discussion because doing some sleep-deprivation training will allow you to practise a few on-the-go sleep strategies, as well as products to counter sleep. But let’s first consider the details of a normal sleep cycle.
The human circadian rhythm is naturally light-dependent and influences physical, mental and behavioural changes over a 24 hour period. Three important bodily functions affected by circadian rhythms include hormone release, eating habits and digestion, and body temperature regulation. Melatonin, which is produced in response to darkness, helps regulate the sleep cycle. Normal human sleep comprises REM (rapid eye movement) sleep and three stages of non-REM sleep - stage 1 (very light,) stage 2 (light) and stage 3 (deep.) In one night we typically cycle through these phases several times in a specific pattern, but the following points are relevant for our purposes:
We fall asleep through stage 1 (very light) and this only lasts a few minutes.
We reach stage 3 (deep sleep) several times in the first 4 hours of sleep, less thereafter.
We cycle through the distinct stages of sleep every 90 to 120 min on average.
Awakening from deeper sleep leads to sleep inertia which can last from 30 to 60 min and causes grogginess, disorientation and poor productivity.
So how do we apply some of these principles of sleep to the DGT Run? This is where it might be necessary to know what your finish time objective for the race is. If you are unsure, visit our previous blog How Slow Can You Go to calculate your predicted moving time and speed, finishing goal and sleep allotment. This will help you in selecting your during-race sleep strategies.
The first general recommendation for non-stop, multi-day events is to sleep in the first 24 hours of the race in order to avoid sleep debt later on. With an afternoon start this could be tricky as the race adrenaline may make sleeping on the first night challenging. One of the major concerns for sleeping during team events is that both members may not be tired simultaneously. Does the team push on with one sleep-walking, falling over member, or do they stop so one can sleep and have the other sitting shivering in the cold, very much awake and “wasting time?” Difficult conversations to have in the graveyard hours between two sleep deprived athletes! Know your partner… ;)
Considering the natural sleep cycle, it may be advisable to adopt different approaches to sleep at various stages of the race. Early on, longer periods of sleep can be “banked” by sleeping for about 4 hours at a time, somewhere between 10pm and 4am. This should allow you to get most of your normal deep sleep, which will be very beneficial for recovery and performance. Mid-race shorter sleeps of 90 minutes to 2 hours would provide just one cycle of deep sleep while still allowing you to awaken in the light sleep or REM phase. Ideally you will never rise directly from the deep sleep phase as the negative effects of sleep inertia will have you stumbling along, possibly in the wrong direction, for about half an hour.
In the latter part of the race you can manage sleep deprivation with short naps of anything from 2 minutes to 45 minutes. Under 5 minutes is commonly known as a “power nap” and in this time you’ll still be in the lightest stage of sleep, so getting going again will be easy. Closer to 45 minutes will give you more quality sleep in stage 2, but you do start tending closer to that grey area of experiencing sleep inertia. One study on the effects of sleepiness on performance in night-shift workers found that naps between midnight and 4am that lasted up to 50 minutes demonstrated a benefit on reaction time, lapses, memory recall, and driving performance.
Fortunately, there are also a few useful tricks for returning to the world of the living after these shut-eye periods. One is to time your sleep so that you awaken naturally with sunrise and your normal circadian rhythm. If this isn’t possible, washing your face and using a bright light (or in this case, putting new batteries into your head light and using it full strength for a few minutes) can help too. On nights of full sleep deprivation consider changing your headlight batteries in the early hours of the morning anyway. Lights can fade quickly when they start to die but fatigue may reduce your ability to notice, and a faint light is not conducive to productive movement or staying awake. Another tactic frequently employed in mountainous environments is to sleep at times when you know that a fall in body temperature will wake you up. This is most likely to be effective in the early hours of the morning as our core body temperature is naturally lowest around 2-4am and this coincides with low environmental temperatures. So taking a nap at midnight will probably have you waking from cold about 2 hours later.
Caffeine as a mental stimulant is a popular choice to help ward off fatigue when taking a nap isn’t possible. Caffeine works by blocking the effect of a natural substance called adenosine which accumulates in the body throughout periods of wakefulness. After approximately 12 to 16 hours high levels of adenosine start to cause drowsiness and it is this effect that caffeine inhibits. Many studies have shown its physical effects in improving endurance, speed and stamina, as well as its mitigation of neurobehavioural impairment during sleep deprivation. One particular study tested the effect of a 200mg dose versus a 300mg dose of caffeine, administered 6, 18, 30, and 42 h into wakefulness. They found the difference between the two doses to be negligible but the improvement in performance to be twice that of a placebo (no caffeine) and adverse effects of caffeine were minimal.
While a good cappuccino may be difficult to find on the mountain, caffeine capsules can be useful. The onset of effect is typically between 20 to 45 minutes post ingestion, and the duration of action about 3 to 5 hours. Under normal circumstances then caffeine consumed right before taking a nap could be expected to wake you up around 45 minutes later. To stay alert right through the night may require repeat doses of caffeine. The exact values, doses and timing, however, will differ between individuals so it’s best to test caffeine products in training before the event. Some athletes do not respond to caffeine at all while others do not respond well, so it’s important to know your own body here.
If caffeine is not your cup of tea (pun intended!) there is also the option of consuming sugary snacks intermittently through the night. Sugar has been proven to increase wakefulness and reduce sleep quality, so it can certainly aid in keeping you awake. A study testing driving ability in a simulator after a full night of sleep deprivation found that 1g of sugar per kilogram body weight improved the ability of subjects to stay alert. One thing to bear in mind is the body’s reduced ability to digest food and therefore poorer food tolerance at night. It may be advisable to follow your normal meal times as closely as possible when it comes to dinner and breakfast, rather than having full, heavy meals between 10 pm and 4am. Try to keep your midnight snacking to just that - snacks as necessary.
The last topic I’d like to discuss is where to sleep and safety. While the factors at play here are numerous, I’ll mention just a few points worth consideration. Firstly, in rain or bad weather it is valuable to find a small shelter or even just a protective rock to nap behind. Sleeping in a bivvy bag out in the open is not going to give good quality rest in poor conditions. During heavy thunderstorms be cognisant of sleeping near streams or rivers. Even in Lesotho where the terrain is gentle, flash flooding can occur. Secondly, if sleeping at night, aim to sleep at the base of a climb. This will allow you to warm up as soon as you start moving again. If you or your partner has particularly low cold tolerance, aim to sleep during the afternoon rather. A natural circadian dip between 2 and 6pm can help you fall asleep in this period. Set an alarm (or two!) to wake you after the desired period, accounting for about 10 minutes to fall asleep. The third factor to account for is the Basotho villages, especially in the deeper Lesotho sections of the route. For peace of mind and quality rest it is advisable to sleep away from the trail and preferably not in the more densely populated areas. Closer to the escarpment and Lesotho-South Africa border should offer more quiet spots as well as more rocky nooks and crannies for shelter, while the Sani Pass aid station will of course make for a good sleeping point before the last third of the race.
To conclude, I want to stress the importance of having a sleep plan for your DGT run and then being flexible in how you apply it. Just “winging it” will most likely see you pushing for too long in the beginning and becoming severely fatigued later in the race. In such states of severe sleep deprivation it will be difficult to move efficiently, navigate accurately, fuel yourself sufficiently and co-operate well as a team. Try to remember that sleeping is not a waste of time nor is it time lost. It’s an essential part of your strategy for a successful race!
Photo Credit: AdventureLifeSA
