see also:

• bushwalking in Australia
• the problem with cold air whilst camping
• keeping warm when camping or hiking
• tips for better sleeping when camping
• camp ground etiquette
• chill out and de-stress by car camping comfortably
• how to sleep comfortably and healthier at 7deg C without a sleeping bag

• the hiking world is divided on whether it is best to sleep naked or not when camping
• exposed skin on a healthy resting adult person becomes too cool and uncomfortable when air chill temperatures drop below 19-20degC (most comfort for a resting person is 22-24degC), and you are likely to start shivering if chill temperature drops below 15degC
• one can sleep naked under a light quilt comfortably (such as a Sea to Summit Ember II - rated to “2degC” with clothes on) down to around 12-13degC, but at lower temperatures need either:
  • heating to keep a small sealed tent warm, or,
  • an additional thermal sleeping bag liner, or,
  • a warmer quilt/sleeping bag, or,
  • start layering up with clothes

• don't need to carry extra weight of night clothes when hiking
• don't need to sleep in dirty or wet hiking clothes that really need some airing
• reduced skin pressure points from clothing creases and joins when lying on a firm “bed”
• reduced risk of prickly heat rash from your body overheating in a sleeping bag
• mental health self-care - better connection with nature on warmer nights - the sensual feel of a balmy breeze over your body while smelling the fresh clean air is something many people value highly
• reduced sweatiness and resultant cold or fungal skin infections from overheating in a sleeping bag
  • this may reduce risk of groin chaffing, fungal skin issues, and painful scrotal varicoceles
• more options for temperature control giving more comfortable sleep as long as you don't get too cold and shiver - you may need to layer up as the temperature drops overnight
• breathe easier: your 100W body heat output can be used to warm the air inside the tent if ventilation is kept low and if not sleeping inside a sleeping bag.
  • Instead of all that heat being trapped in your sleeping bag giving you a hot body but very cold airways (you will need to lie on a thermal heated cushion if temperatures fall below 15degC otherwise you will shiver)
  • you can feel a bull ant crawling on you far earlier and you can take more gentle and guided actions to remove it without blindly getting it aggressive and stinging you
• live longer - improved body metabolism, insulin sensitivity, cold acclimatisation and improved levels of brown fat stores
  • sleeping cool not only helps you get off to sleep but doing it over a few nights increases the amount of beneficial brown fat stores rich in mitochondria and ability to burn fat and reduce overall obesity (if you don't over-eat to compensate) while providing improved cold tolerance - a win-win outcome
  • exposing people to 6 hours of 15°C for 10 days significantly increased energy expenditure and was also associated with a 37% increase in brown fat
  • Excursions to ambient conditions below the thermo-neutral zone (TNZ) (ie. for a resting naked body, below ambient temperatures of 21-26degC depending upon level of cold acclimitisation) can increase energy expenditure and improve glucose metabolism, and subsequently may reduce susceptibility to obesity and Diabetes type 2 ¹⁾
• potentially improved testicular function due to ability to maintain mandatory low scrotal temperatures
  • the testes are designed to function at lower temperatures and MUST be maintained at 4-5degC below core temperature to function, hence they are outside the body - keeping them hot and sweaty is not good for their health and function and they will retract up into a warmer position if they get too cold
  • children with untreated undescended testes have high incidences of testicular cancer
  • increase in scrotal temperature is associated with impaired sperm parameters (insulating ram scrotums for 8 days resulted in zero motile sperm production which took over 100 days to recover, while a single 20 minute sauna caused a fall in sperm count within one week, which returned to normal ten weeks after the heat exposure²⁾) and higher FSH plasma levels indicating impaired testosterone secretory function
  • this may be particularly important in obese men and those with varicoceles - their scrotal temperatures have been shown to be higher than other men
  • wearing underwear, a willy warmer which covers the scrotum, or sleeping with legs curled up will also overheat the scrotum
  • whether sleeping naked camping makes any difference to sperm quality or testosterone production is unknown but we do know that not allowing the testes to be at the correct temperature DOES impact sperm production for a long time afterwards!
  • of course, exposure to very cold air below minus 15degC will risk frostbite and hypothermia so they need to be covered in freezing conditions

• if you also have your vestibule door open or you have mesh windows for that breeze and connection with nature, this can be a privacy issue
  • you do need to ensure you are not breaking laws of indecent exposure in your country - generally in Australia, you would not be doing so if a person needs to use a torch to see you naked in your tent while you sleep, but nevertheless, one should take precautions to minimise the risk of people walking by seeing you naked by orientation of vestibule door, adding extra visual barriers (including to block passing lights from cars), ensuring you do not use lights inside your tent when people may be able to see you
• your skin oils will build up on your quilt or sleeping bag - so you really should be using a sleeping bag liner to minimise this
• you may still need to layer up if conditions get cold eg. ambient temperatures fall below 12-18degC
  • alternatively, a 12V thermal cushion under you and a quilt on top with warm socks will generally allow minimal layering for temperatures down to around 5degC as a thermal cushion plus a naked body in a thermally closed tent without ventilation will allow air temperatures to be 5-9degC warmer than outside temperatures