question: When a person is tired, why does a hot shower make them feel reenergised afterwards?
comment: Raising your core body temp by a hot shower or bath increases the body's metabolism by a significant margin, meaning that you have access to more energy more efficiently. The term "warm up" isn't just a generic term, being warmer makes it easier to generate energy at the cellular level.
passages: According to a BBC experiment conducted by researchers at Oxford University, counting sheep is actually an inferior means of inducing sleep.
  
  Section::::Activities.:Hot bath.
  
  The daily sleep/wake cycle is linked to the daily body temperature cycle. For this reason, a hot bath which raises the core body temperature has been found to improve the duration and quality of sleep. A 30-minute soak in a bath of  – which raises the core body temperature by one degree – is suitable for this purpose.
   The title arises from the operation of somec, the life extension drug forming the foundation of the interstellar Empire. Somec creates an unbearable, torturous burning sensation throughout the body while pushing the patient to suspended animation. However, the somec process exterminates the user's memory, and so these memories are recorded and stored separately shortly before they go under, to be returned to the body after they have awakened, and so the memory of the process itself cannot be retained. Thus, each somec patient experiences the panic of burning hot sleep "for the first time" (as far as their memory goes) no matter how many times they have taken somec before.
   A systematic review and meta-analysis of 17 different studies finds that taking a warm bath or shower 1-2 hours before bedtime for as little as 10 minutes shortens the sleep onset time and improves sleep efficiency and subjective sleep quality and increases the amount of deep sleep . 
  
  Section::::Activities.:Sex.
  
  Sexual intercourse, and specifically orgasm, may have an effect on the ability to fall asleep for some people. The period after orgasm (known as a refractory period) is often a time of increased relaxation, attributed to the release of the neurohormones oxytocin and prolactin.
  
  Section::::Activities.:Yawning.
   "One" was later placed on their first greatest hits album, "," while the title track would later be placed on their Jacket B edition of their 2012 studio album "Now or Never", which would also be their final album with their leader and lead vocalist Hiroki.
  
  Section::::Music video.
   Section::::Title.
   The National Institute of Mental Health funded a team of doctors, led by Alan Hobson, MD, Robert Stickgold, PhD, and colleagues at Harvard University for a study which showed that a midday snooze reverses information overload. Reporting in "Nature Neuroscience", Sara Mednick, PhD, Stickgold and colleagues also demonstrated that "burnout" irritation, frustration and poorer performance on a mental task can set in as a day of training wears on. This study also proved that, in some cases, napping could even boost performance to an individual's top levels. The NIMH team wrote: "The bottom line is: we should stop feeling guilty about taking that 'power nap' at work."
   Rewarming shock
  
  Rewarming Shock (also known as rewarming collapse) has been described as a drop in blood pressure following the warming of a person who is very cold. The real cause of this rewarming shock is unknown.
  
  There was a theoretical concern that external rewarming rather than internal rewarming may increase the risk. These concerns were partly believed to be due to afterdrop, a situation detected during laboratory experiments where there is a continued decrease in core temperature after rewarming has been started. Recent studies have not supported these concerns, and problems are not found with active external rewarming.
   Shower Shock
  
  Shower Shock is a bar of soap that has been impregnated with caffeine. The manufacturer ThinkGeek claims that when the soap is used, caffeine is exuded in the lather, to be absorbed through the user's skin. However, the idea that caffeine passes rapidly through the skin is unproven, and it has been suggested that the amount absorbed is not significant compared to a cup of coffee. Anecdotal accounts of using this soap also suggest that it is not effective as a delivery method for caffeine.
   Navy showers originated on naval ships, where supplies of fresh water were often scarce. Using this method, crew members were able to stay clean, while conserving their limited water supply. The concept has also been adopted by some other people who wish to conserve water and the energy needed to heat the water, for both environmental and economic reasons. According to the U.S. Department of Energy, water heating is typically the second-largest energy expense in homes (after space heating).
   Consequently, hot or cold environmental temperatures can reduce the proportion of REM sleep, as well as amount of total sleep. In other words, if at the end of a phase of deep sleep, the organism's thermal indicators fall outside of a certain range, it will not enter paradoxical sleep lest deregulation allow temperature to drift further from the desirable value. This mechanism can be 'fooled' by artificially warming the brain.
  
  Section::::Physiology.:Muscle.
   Hot Summer (song)
  
  "Hot Summer" is a song by German pop group Monrose from their second studio album, "Strictly Physical" (2007). A dance-pop song with heavy elements of Europop and house, it written and co-produced by Danish songwriters Remee and Thomas Troelsen.
   Common medicines known to cause this problem are eszopiclone, zolpidem, and anxiolytics such as benzodiazepines and which are prescribed to people having difficulties falling or staying asleep.
  
  Rebound depression
  
  Depressive symptoms may appear to arise in patients previously free of such an illness.
  
  Daytime rebound
   Hot cycling
  
  Hot cycling refers to a spin class performed in a room heated between 80 and 84 degrees Fahrenheit. Like hot yoga, which uses heat to increase an individual's flexibility in the poses. Heated exercise at temperatures of 100 degrees Fahrenheit has also been shown to strengthen the immune system and increase the volume of oxygenated blood which can lower cholesterol.
   The music video for "Summer Madness" was predominately centered around the group, Hiroki, Shinya, Keita and Akira, on their way to and arriving at a beach. Sections of the video showed the members in front of a mall, while each performed solo vocals as the other members played in the background. Other clips featured them inside a mall, donning summer-themed attire while partaking in comedic moments. 
   Power naps restore alertness, performance, and learning ability. A nap may also reverse the hormonal impact of a night of poor sleep or reverse the damage of sleep deprivation. A University of Düsseldorf study found superior memory recall once a person had reached 6 minutes of sleep, suggesting that the onset of sleep may initiate active memory processes of consolidation which—once triggered—remains effective even if sleep is terminated.
   To help promote the single, the music video for "Hot Time" was released for the holiday season in December, most likely due to the story of "The Little Match Girl" taking place between Christmas and New Year's Eve.
  
  Section::::Girls meet Beauty.
  
  Prior to the single's release, misono took part in the weight loss reality program "Girls meet Beauty." The program was a three-month duration in which the patient would closely monitor their calorie intake and increase their overall exercise regimen.
   Sara Mednick conducted a study experimenting on the effects of napping, caffeine, and a placebo. Her results showed that a 60–90-minute nap is more effective than caffeine in memory and cognition.
  
  Section::::Stimulant nap.
   It is common to hear people say, "gokuraku, gokuraku" when they get into the bath. It means something to the level of divine pleasure; it is a good feeling for the body and the soul.
  
  Section::::Etiquette.:Equipment.
   Temperature and pain are thought to be represented as “feelings” of coolness/warmness and pleasantness/unpleasantness in the brain. These sensory and affective characteristics of thermoregulation may motivate certain behavioral responses depending on the state of the body (for example, moving away from a source of heat to a cooler space). Such perturbations in the internal homeostatic environment of an organism are thought to be key aspects of a motivational process giving rise to emotional states, and have been proposed to be represented principally by the insular cortex as feelings. These feelings then influence drives when the anterior cingulate cortex is activated.
   In contradiction to previous studies, it has been found that there is no effect of body temperature on performance on psychological tests. This is likely due to evolutionary pressures for higher cognitive function compared to the other areas of function examined in previous studies.
  
  Section::::In mammals.:Outside the "master clock".
   Section::::Physiology.:Thermoregulation.
  
  Brain temperature has been shown to drop when a sleeping EEG is exhibited in one or both hemispheres. This decrease in temperature has been linked to a method to thermoregulate and conserve energy while maintaining the vigilance of USWS. The thermoregulation has been demonstrated in dolphins and is believed to be conserved among species exhibiting USWS.
  
  Section::::Anatomical variations.
  
  Section::::Anatomical variations.:Smaller corpus callosum.
   In 1976, it launched the "Miralec" brand of shower with temperature stabilisation. "Mira Thermostatic" replaced the "Leonard" brand. In 1978, it launched its first instant electric shower. In 1979, the "Rada" brand was introduced to sell the "Mira" showers in export markets. In 1981 it introduced a thermoscopic electric shower for the domestic market.
   A warm up generally consists of a gradual increase in intensity in physical activity (a "pulse raiser"), joint mobility exercise, and stretching, followed by the activity. For example, before running or playing an intensive sport, athletes might slowly jog to warm their muscles and increase their heart rate. It is important that warm ups be specific to the activity, so that the muscles to be used are activated. The risks and benefits of combining stretching with warming up are disputable, although it is generally believed that warming up prepares the athlete both mentally and physically. In a meta-study of 32 high quality studies, about four-fifths of the studies showed improvements in performance.
   Heat syncope occurs in a warm environment when blood pressure is lowered as the body dilates (widens) arterioles (small blood vessels) in the skin to radiate heat. This condition occurs within five days of heat acclimatization, before the blood volume expands. The result is less blood to the brain, causing light-headedness and fainting when a person stands up quickly or stands for a long period of time. Those who perform strenuous work outside in warm climates are at particular risk.
  
  Section::::Diagnosis.
   The phrase "hot autumn" has since been applied in the Italian press to describe other periods marked by significant strikes, although in later decades, such seasonal strikes have more often been directed against government's budget plans, which are usually planned and publicly debated during the autumn months.
  
  Section::::Origins.
  