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#WHOOPEd Digest, Vol. 37

By Allison Isham

#WHOOPEd Digest, Vol. 37

You may be dehydrated long before you feel thirsty, the effect of mental stress on the autonomic nervous system, and why “sleep debt is carcinogenic.”

University of Arkansas research study suggests athletes may actually be dehydrated well before they feel thirsty: “Dehydration Impairs Performance, Regardless of Thirst”

  • Stavros Kavouras is the director of the hydration lab at the University of Arkansas. He and his team conducted a study on hydration status by “blinding” seven cyclists who were exercising in hot, dry conditions.
  • The cyclists were delivered body-temperature water directly to their stomachs via the use of a nasogastric tube. “One group received adequate water through the tube and the other group did not.”
  • Cyclists who were not given adequate water had higher core temperatures and performed worse on speed and power outputs compared to the cyclists given adequate water.
  • Kavouras points out two factors outside of dehydrations that may lead to performance impairments:
    • When you know you are dehydrated, you potentially believe you will perform badly
    • The feeling of thirst itself is miserable
  • Hydrate, hydrate, hydrate throughout the day. Did we mention that HRV is affected by hydration?

The sleep epidemic is real, especially in elite athletes who face issues like increased core temperature following exercise, psychological stress, frequent travel and regular fatigue/pain.

  • According to some researchers, “sleep is reported to be the single best psycho-physiological recovery strategy available to elite athletes.”
  • We know that objective ways to measure sleep include methods such as polysomnography and actigraphy, but understanding the athlete’s subjective measure of their sleep is of equal importance.
  • Cheri Mah et al., developed an athlete sleep behavior questionnaire to help identify maladaptive sleep practices.
  • 564 participants participated in this study; 242 were athletes while 322 were non athletes.
  • The study found a significant difference between athletes and non athletes for the Athlete Sleep Behavior Questionnaire (ASBQ) global score. Overall the ASBQ is a valid and reliable tool which can really help understand elite athletes and their sleep behaviors.

As two international teams prepare to play at Mile High Stadium in Denver, one is planning to combat jet lag and fatigue with melatonin, blue light therapy and humidi-flyer technology.

  • England took on New Zealand at Mile High Stadium in Denver. Each team had to uniquely prepare to compete at high altitude in the middle of summer.
  • The New Zealand Rugby League is hoping to combat jet lag, fatigue and injuries by giving athletes melatonin for the first three days in the US. The team will also be using blue-light therapy and humidi-flyer technology.
  • Humidi-flyer masks “prevent dehydration by trapping the expired moisture from breath, which is then used to humidify the air inhaled. The mask is said to prevent jet lag as well as protect the wearer from the spread of viruses.”
  • Blue light therapy exposes athletes to natural or violet light in order to combat sleep and mood disorders.

Many NCAA teams will only use external load monitors during practice or games. What about the other 22 hours in a day? Mental stress can affect the autonomic nervous system equally. Odds of an injury/illness double during high academic stress.

  • One key factor that may help better understand the link between academic stressors and injuries is psychoneuroimmunology (PNI). PNI is the study of interactions between behavioral, neural/endocrine function and immune processes.
  • Holmes et al., reported that “50% of the athletes who experienced high life stress during the year before football season incurred injuries that required them to miss 3 days of practice or 1 game,” which meant substantially more missed playing time than athletes with moderate or low stress.
  • The study by Mann et al, found that psychological stress, not just physical stress alone, plays an important role in the occurrence of physical injuries for college football players.
  • The autonomic nervous system takes into account holistic stressors!

“One very important research question is whether longer term changes that occur after brain injury are helping to restore function after damage or are harming prospects for recovery.”

  • When it comes to brain injuries, the damage doesn’t stop after initial impact. Change in the brain continue to evolve post-injury, sometimes months after.
  • “One example of changes in the brain that might help restore function is change in the structure of the white matter, or wiring of the brain.”
  • “Another form of adaptation to restore function after injury in the strengthening of pre-existing circuits that were in use prior to injury, thereby restoring them to their former level of performance.”

If you live by the mantra, ‘I can sleep when I’m dead’, here are a few stats for you: Sleepiness is a probable carcinogen (breast cancer, prostate cancer and colon cancer). Just a week of short sleep (5-6 hours) can make you pre-diabetic.

  • Matthew Walker, a neuroscientist who directs the sleep and neuroimaging lab at UC Berkeley, gives this advice; “the shorter your sleep, the shorter your life.”
  • Walker outlines three ways a lack of sleep can hurt both brain and body:
    • “Lack of sleep puts the immune system at a disadvantage.” — Lack of sleep depletes stores of lymphocyte (white blood cell). A single bad night of sleep (4-5 hours) could lower lymphocyte count by 70%.
    • “Just an hour of lost sleep can kill.”
    • “Sleep debt is carcinogenic.” — Cancer can find a breeding ground within insufficient sleep.

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