Tag Archive: sleep

1. Does sleep affect sporting performance?

   20th June 2017 9:26 am Leave a Comment

   How can sleep affect sporting performance?

   

   Circadian rhythm

   A recent BBC article highlighted the variations in sporting performance for individuals at different times of the day (1). These differences are down to biological processes which change throughout the day.

   These changes are controlled by our internal body clock, which is affected by our external environmental cycle, and are known as Circadian Rhythm. Here Matt will describe what Circadian Rhythms are and how they work, as well as suggesting practical ideas for maximising your sporting performances.

   What is a Circadian Rhythm?

   A Circadian Rhythm is a biological rhythm which roughly follows a 24 hour period, going through day and night (light and dark). Humans (and other animals, plants and micro-organisms) react to these changes in light to regulate sleep and activity through functions such as heart rate, respiratory rate, body temperature, hormones (particularly cortisol and melatonin) and cognitive function (α, β, θ, δ waves).

    How does it work? 

   As diurnal animals (awake during the day, as opposed to nocturnal), humans respond to light as a stimulus to wake up. Light hits the optic nerve of the eye and travels to a part of the brain called the Suprachiasmatic Nucleus (SCN), a group of cells in the hypothalamus.

   The SCN signals other parts of the brain to increase body temperature, produce the hormone cortisol, and reduce the production of melatonin, which is linked to sleep onset and is produced when the eyes signal darkness.  It should be noted that humans do have an internal circadian rhythm which is present even in constant conditions with no light. However, this rhythm is far less pronounced than during real life conditions.

   So how does this affect performance? 

   As our physiology changes throughout the day, different elements of our physical fitness will have an optimal time period for performance.  A recent review of the literature  found that tests of mental acuity, accuracy and fine motor skills were best performed in late morning (2). This was due to a combination of optimal arousal levels and limited levels of fatigue.

   On the other hand, tests of strength, speed, aerobic and anaerobic endurance were shown to be most successful when performed in late afternoon/evening. This is possibly due to increased heart rate (and thus cardiac output), ventilation rate and core body temperature.

   These factors would mean that VO₂ max would be optimised during this period and suggests a possible reason for this phenomenon.

   There have been suggestions that external factors such as weather conditions (e.g. heat) mean that performance is enhanced in the evening compared to earlier in the day. However, studies have shown that swimmers subjected to constant environmental conditions perform best during late afternoon/evening, even when they are used to training at different times such as early morning. This suggests a considerable affect of circadian rhythm on performance.

   For strength training, there was a smaller difference in performance at differing time periods for females than there was for males. It has been suggested that this could be due lower levels of muscle mass, or possibly that central governing plays a bigger role for strength based activity in females.

   Is the circadian rhythm constant?  

   

   Sleep routine

   As the name suggests, Circadian rhythms follow a regular pattern, as long as environmental conditions remain regular. Humans become entrained to their environment, as shown since the industrialisation of the world.

   Changing work patterns (shift work, less exposure to sunlight, etc) and exposure to artificial light have impacted our sleeping/waking patterns, with many people waking before the onset of natural light, and other even working throughout the night and sleeping during the day.

   In many cases, this can lead to sleep deprivation, which will have a negative impact on both health and performance.  Read here for more information on sleep deprivation.

    Is everyone the same?  

   

   Sleep deprived teenager

   People have long been classified into groups based on sleeping habits, morning/evening person, lark/owl etc. Research has shown that this is due to variations in circadian rhythms (3).

   Subjects lived under normal conditions for several days and their onset of sleep was measured, with the expected variations in sleep time observed. Subjects then lived for several days in constant conditions with no light or indication of time of day. Each subject quickly reverted to their natural free running rhythm, some being slightly less than 24hours, and some being slightly more.

   There was a direct correlation between time of sleep onset and length of free running circadian rhythm:

   •  -Early sleepers=shorter free running rhythm
   • -Later sleepers=longer free running rhythm

   So although our circadian rhythm can be affected by environmental factors, individual differences will still play a part in optimal performance time. 

   Does Circadian Rhythm vary with age?

   Circadian rhythms are subject to much change over the course of our lives. While measuring sleep patterns, researchers have found that peak sleep time became later as children grew into their teens.

   After adolescence, peak sleep time became earlier. This change during adolescence is due to alterations in the production of the sleep hormone melatonin. Levels of melatonin in the blood rise more slowly in teenagers than in children and adults, meaning they don’t start to feel tired until later in the evening.

   This in turn affects their natural waking time. As teens would usually need to wake early for school there is a risk of not getting enough sleep. This can prolong the “circadian dip” and result in teenagers not starting to feel awake until later in the morning. Practices such as keeping lights dimmed during the evening and getting exposure to bright light early in the day can help.

   Summary and Practical advice

   Circadian Rhythm controls the biological processes which affect our physical performance e.g. heart rate, body temperature, hormone production and cognitive function.

   Activities involving accuracy, mental acuity and fine motor skills are best performed during late morning, when alertness levels are high but fatigue levels are low.

   Speed, strength and endurance activities are performed most successfully in the late afternoon/evening, as body temperature and heart rate are elevated compared to earlier in the day, meaning cardiac output and oxygen uptake are increased.

   Humans can become entrained to certain environments, so if an athlete is preparing for a competition at a certain time of day, it is advisable to adjust their daily routine accordingly.

   For example, an athlete who is used to getting up late in the morning and training in the early evening needs to prepare for a competition that starts at midday. In this case, the athlete would be wise to prepare for the event by adjusting their sleep pattern (going to bed earlier and waking earlier) and altering their training time (to match that of the competition) in order for the body’s rhythm to adjust.

   Here are some useful sleep strategies to help you get into a good routine:

   • By establishing a bedtime routine, the chances of getting a good night’s sleep increase.
   • Very hard training sessions and training late in the evening can lead to sleep disruption.
   • Diet is very important in getting good sleep. Eating late at night, eating spicy foods and consuming caffeine can disrupt sleep directly by stimulating the body and also indirectly by affecting the digestive system which can awaken athletes during the middle of the night.
   • Within 1 hour of you wanting to go to sleep, avoid television, it may seem relaxing, but it is actually an exciting activity that is a distraction, not an aid to relaxation.
   • Reading a book, listening to relaxing music or relaxation tapes are suitable ways for spending the hour before sleeping.
   • Drinking milk, warm or cold may help you get to sleep.
   • Any distraction or worries that you may have, things that you have to think about the next day, sort out before your hour before sleep. Write down in your diary anything you have to do the next day, keep a pencil and paper by your bed, the act of writing something down is a good way to eliminate it from your immediate thoughts.
   • Conducting a Progressive Muscular Relaxation programme will help your body prepare for sleep.
   • Ensure that your bedroom is a place for sleeping. Watching T.V. in bed is not going to help you relax. The room should be well ventilated, a comfortable temperature, cooler is better. The curtains or blinds should be thick and keep the room dark. Putting lavender oil on your pillow may help you get to sleep.
   •  If you do not fall asleep within 20 minutes, then get out of bed and do some activity that will distract you – mundane household chores such as ironing, or reading will help.
   • If you awaken in the middle of the night to go to the toilet, and then can not get back to sleep within 20 minutes, again get up and do something. Keep the lighting level low, as bright light will encourage the body to remain awake.
   • If you have something on your mind during the night, it may be best to get up and actually tackle the task for an hour, then try to return to sleep. If that means writing a document, doing some college work, or working on your budget problems, then doing it may help alleviate the worry.

   Matt Durber

   References 

   1. Gallagher, J. (2015) Bedtime “has huge impact on sport” BBC.
   2. Drust, B., Waterhouse, J., Atkinson, G., Edwards, B. & Reilly, T. (2005) Review: Circadian Rhythms in Sports Performance- An Update Chronobiology International, 22 (1), 21-44.
   3. Merrow, M., Roenneberg, T., Madeti, C., Goedel, M. & Lenssen, D. (2015) “Circadian Clocks: How Rhythms Structure Life” Ludwigs-Maximilians-Universität in Munich. Available at https://www.coursera.org/course/circaclock

2. How much sleep is enough after training?

   10th March 2016 2:49 pm 16 Comments

   A Guaranteed, Free and Easy Way to Improve Performance…

                                                   SLEEP

   In a recent workshop we ran, every athlete was found to be SLEEP DEPRIVED. Find out how this can impact on your sporting performance here.

   In that little training diary that any successful athlete keeps, will be a history of:

   • the exercises they perform
   • the weights they lift
   • the foods they eat
   • how they feel (RPE -rating of perceived exertion) and ….
   • how much sleep they are getting

   Why we document exercises, weights, nutrition and RPE and how they affect training and performance is well understood, but why do we keep a sleep diary?

   Sleep has been shown to have a big impact on sporting performance as well as potentially changing the physiological effects of training.

   This article aims to highlight the importance of sleep for athletes and how it affects training and performance.

   Evidence of the effect of sleep on performance

   Studies have shown that sleep deprivation has lasting negative impacts on health!

   Sleep deprivation has an impact on the body’s metabolic and endocrine functions, with some of the effects listed below:

   • Affect glucose metabolism and appetite (Van Cauter & Spiegel,  1999)
   • Have a negative impact on the brain and cognitive function
   • Reduced immune system
   • Increase Cortisol levels (stress Hormone)
   • Affect on growth Hormone
   • Increased injury risk due to reduced muscular control

   Dr. William C. Dement, a sleep researcher at Stanford University, suggests that:

   “that alleviating the burden of sleep debt could save thousands of lives every year.”

   Cheri Mah who has been studying the sleep patterns of Stanford University athletes over the last few years has found increasing sleep has led to improved sports performance for all types of athletes (Mah et al, 2009).

   One specific study on University swimmers found increasing the athletes sleep to 10 hours a night improved their 15m sprint time, start reaction time and increased their kick strokes.

   She also replicated these findings in American Football athletes with increased sleep improving their 20 yd shuttle time and 40 yd dash time.

   With evidence that sleep deprivation can physiologically and psychologically affect individuals and evidence of increased sleep improving sporting performance, are you getting enough?

   Why does sleep affect trainability and performance?

   Firstly and most importantly sleep is very important for recovery.

   Sleep deprivation has shown to

   1. increase cortisol levels,
   2. decrease activity of human growth hormone,
   3. and reduce the efficiency for glucose metabolism.

   All of these things can affect our sporting performance (Samuels, 2009).

   In addition when we are tired concentrating is hard and our reaction times are slower, not great for competition!

   On top of these physiological changes sleep deprivation is also shown to reduce cognitive function and therefore reduce the ability to learn a new skill.

   Effect of Glucose metabolism

   So why is glucose metabolism important?

   The energy we require for any exercise comes from the metabolism of glucose. If this source of energy isn’t readily available then our body is unable to perform at its best.

   Food is our fuel but if we are unable to convert our fuel into energy then it becomes useless!

   Sleep deprivation also impairs the ability of our body to store glycogen so our energy stores are depleted, something that will hamper your preparation prior to a big competition!

   Effect of Cortisol

   Cortisol is more commonly known as the stress hormone. Sleep deprivation has been shown to increase the levels of this particular hormone.

   With cortisol the athlete will often feel irritable and short-tempered as well as have a lack of energy.

   Effect of Human Growth Hormone (HGH)

   Everybody knows rest and recovery are important or high-level performance as it gives the body time to repair and strengthen itself. HGH is the hormone responsible for stimulating this growth and repair.

   HGH is actively required for this tissue repair by stimulating growth via cell reproduction and regeneration. It is naturally produced by the pituitary gland in the brain and is a protein based peptide hormone.

   If our HGH levels are low or not doing their job properly then it can result in a decrease in muscle mass and energy levels.

   Therefore with sleep deprivation affecting the efficiency of this hormone you can see why it is not great for sporting success!

   Am I Getting Enough Sleep?

   This is the big question and below are some guidelines to help you answer it.

   It is recommended that adults get 7–9 hours of daily sleep and 9-10 hours of daily sleep for adolescents and teens!

   If you fall asleep within 20 minutes of going to bed and wake without an alarm you are probably getting enough sleep say sleep experts.

   However if you fall asleep as soon as your head hits the pillow and wake to an alarm you are probably sleep deprived!

   So I will leave you with a few tips to ensure sleep is not a factor hindering yours or your athlete’s performance:

   1. Firstly and most importantly make sure you are getting enough sleep (hours highlighted above).
   2. You can achieve the above by prioritizing sleep as a part of your regular training regimen (noting it in your training diary).
   3. Go to bed and wake up at the same times every day, get into a pattern.
   4. Take brief 20-30 minute naps to obtain additional sleep during the day, especially if training hard.
   5. Increase your sleep time several weeks before a major competition to ensure you are not sleep deprived!
   6. Switch off your phone/ tablet an hour before you go to bed: the blue light can reset your circadian rhythm to a later time, making it harder to fall asleep.

   I hope this article has highlighted the importance of sleep for athletes wanting to be at their best? It really is the #1 Recovery supplement

   Sweet dreams…

   Fran Low
   

   For further information on how sleep deprivation can lead to overtraining, read our free ebook here

   References

   Van Cauter E, Spiegel K (1999). “Sleep as a mediator of the relationship between socioeconomic status and health: a hypothesis”. Ann. N. Y. Acad. Sci. 896: 254–61

   Mah, C. (2008). Extended Sleep and the Effects on Mood and Athletic Performance in Collegiate Swimmers. Annual Meeting of the Associated Professional Sleep Societies.

   Samuels, C. (2009). Sleep, recovery, and performance: the new frontier in high-performance athletics. Phys Med Rehabil Clin N Am. 20(1):149-59, ix.

3. Recovery Strategies for commited sports people

   9th March 2016 6:38 pm 7 Comments

   The Recovery Pyramid

   I use a pyramid method of recovery when coaching my athletes- there is little point going onto the next level until you have done the first. The further down you go, the less proven are the strategies.

   You will notice that many of these require minimal cost. This may seem unusual to you.

   That is because most recovery methods you hear about are trying to sell you something! Sleep is free, as is water (mostly).

   

   1. Cool down 10-15minutes of movement at 50% of maximum effort.
   2. Fluid and fuel intake within 15mins post exercise. main meal within 2 hours. 1.5 litres of water for every kg lost or for every hour of exercise (depending on climatic conditions). This should contain some protein and carbohydrate. A banana sandwich, Apple and Greek Yoghurt, and a glass of whole milk are all nutritious.
   3. Contrast showers- 30secs hot\ 30 secs cold four sets, then normal shower.
   4. Massage- self or other if you are lucky.
   5. Relaxation– may not help physical recovery, but it can help deal with stress of competition, allowing better quality sleep, which will then assist physical recovery.
   6. Ice bath– may be especially beneficial after contact sports or excessive volume.
   7. Compression suits– might be useful for journeys after competition where you are sat down for a long time. Could be useful on flights too. Avoid sleeping in them as they create too high a body temperature. Never, ever train in them.

   I see many athletes wearing expensive compression suits, but neglecting the simple, cheaper and better proven methods of recovery. (see recovery infographic).

   These are all designed to help you sleep better, which is the Number 1 recovery tool.

   Coaches should look at allowing time for these recovery strategies to take place, especially when you are competing on a weekly basis.

   The sooner you recover, the sooner you can train again.

4. Sleep deprivation

   21st January 2014 2:36 pm 1 Comment

   Does one bad night’s sleep affect performance?

   If you are worried about poor performance after having a bad night’s sleep, that is normal behaviour. The good news is that losing one night’s sleep is unlikely to affect you physically.

   Instead it affects your mood and your motivation to train.

   Sleep appears to be most important for restoration of cognitive functions. Normal rest is adequate for somatic recovery. That is why an afternoon nap is helpful in providing recuperation for both work and training later in the day.

   A recent study on sleep loss and weightlifting performance looked at the effects of 24 hours without sleep.

   It appears that being motivated to train is the most important factor to deal with sleep loss in the short term.

   Further reading

   • How much sleep do I need after training?
   • Chronic sleep deprivation and diabetes.

5. What are the Demands of Wimbledon Tennis?

   24th June 2012 2:22 pm 1 Comment

   Are you inspired by Wimbledon?

   With Wimbledon starting today, we thought it would be good to to look at the requirements of tennis for all abilities and how aspiring players can improve. Duncan Buckmaster has done the research and here are his thoughts.

   

   Physical demands of Tennis

   Grand Slam tennis is a knockout tournament; matches are the best of 5 sets, to get to the final a player will have played 7 matches over 2 weeks.

   A set is the first person to 6 games with a 2 game margin, the game will go to a tie break should it be 6-6 in games, unless in the last set when the players continue playing games until a two game lead is won.

    in 2010 at Wimbledon the final set of a 1^st round match went to 70-68 games, the match in its entirety lasted over 11 hours.

   A game is scored 15, 30,40 then game or if 40-40 it goes to deuce and then advantage, this can continue until a two point lead is won.

   Endurance demands of tennis

   Tennis is a game of high intensity, short duration bouts requiring explosive reactive movements and shots with a variety of rest periods. There is a maximum rest of 20 seconds between points and 90 seconds between games and 2 minutes between sets which are set by the governing body.

   There is some debate on which energy system is provides a foundation during a tennis match. Work done by Fox & Matthews (3) almost 40 years ago stated that 80% of work is done by the Adenosine Triphosphate (ATP) system, however, other research has suggested that the aerobic system is the primary aid to restoring ATP throughout a match.

   Commonly we assume working on our aerobic capacity will always improve our athletes, these is normally done with longer less intense workouts. These theories are based on research that shows fatigue can reduce ball velocity and increase injury risk. (1)

   However, research by Hoffman et al (2) has suggested there is a limit to which aerobic training aids improvements, Kovacs (1) suggests VO2 max of between 55-65ml-kg-1 are beneficial but above this further improvements are redundant.

    Speed and Agility for Tennis

   With video analysis now available several studies have been done on distances travelled during matches, this will depend on the level you play, the surface you are playing on.

   Some stats that have been found over these studies:

   • 80% of strokes played with less than 2.5m movement,
   • 5% of stokes played require more than 4.5m movement,
   • An average of 4 directional changes made during a point,
   • Over 1000 directional changes made during a match,
   • 70% of movements are lateral,
   • 20% of movements are forwards,
   • 8% of movements are backwards.

   Flexibility & Mobility for Tennis

   Due to the single sided nature, shots and surfaces; flexibility is a key area of concern among many tennis players. From young age many players will have solely played tennis which could mean they are one side dominant, they have not had a variety of sports to give their body a rounded education of movement.

   From a young age we start to lose this flexibility due to the amount of time spent sitting at school/work or and then going home and sitting down all evening.

   Being inflexible can have a knock on affect on other parts of the body due to how our bodies compensate for weakness. Three examples of how a lack of flexibility can affect
   a tennis player:

   1. A tight pectoral (chest) muscle will pull the shoulder forward in posture; the muscle will be weaker due to its tightness, this will mean the body has to compensate to find power, which could mean the hips & back rotate more giving an inconsistent shot.
   2. A piriformis (a muscle deep inside the bum) in spasm (constantly tight) can cause pelvic immobility; which can mean the lower back muscles tighten, and the thoracic upper part of the back rounds more to create an illusion of mobility.  This would mean that during a forehand shot the shoulder would need to find mobility and power putting the shoulder joint at risk of injury.
   3. A tight hamstring can result in a lack of knee stability, which could lead to injuries due to the lunging nature of tennis. The sciatic nerve which runs the length of the body could also be affected, so when you serve muscles will tighten to protect the nerve causing an inconsistent serve.

   (Information on Common tennis injuries and how to prevent them here.)

    Strength & Power for Tennis

   Over the last 30 years the styles of play have changed from a flowing style to a more powerful style where player try’s to overpower their opponent. If we look at how modern players like Nadal compared to a player from 30 years ago John McEnroe, we can see a difference in musculature.  

   

    

    

   Power requires a good foundation of strength (4), this is so that the movement is controlled and consistent.

   Part 2 on Wednesday: How to get fit for Tennis.

   For a comprehensive training programme that fits into your schedule, try our Sports Training System

    References:

   1. Kovacs, MS (2006)
   Applied Physiology of tennis performance. Brit. J. of sports Med. 40:381-386

   2. Castagna, C, Manzi,
   V, D’Ottavio, S, Annino, G, Padua, P, Bishop, D. (2007). Relation between
   maximal aerobic power and the ability to repeat sprints in young basketball
   players. J. Strength Cond. Res. 23:963-966

   3. Fox, EL, Matthews,
   DK. Interval training: Conditioning for sports and general fitness. Exercise
   physiology: Theory application to fitness and performance (5^th Ed.)
   1974, P:426,2004

   4. Asci, A, Acikada, C
   (2007). Power production among different sports with similar maximum strength.
   J. Strength Cond. Res. 21:10-16