It's no fun going to bed feeling cold and miserable when you’re out in the wilderness. In New Zealand the weather can be changeable and throughout the year temperatures can get chilly overnight. Here are some simple tips to help you warm up and stay warm when camping out in the cold.
Have the right gear
Warm, dry clothes - Make sure you wear dry clothes when going to sleep – if possible change out of dirty, sweaty, damp clothing. Warm insulating clothes like synthetics and wool maintain your body heat – generally adding extra layers will make you warmer (don’t overdo it though). Wear a good pair of socks to prevent cold feet and wear a warm hat as a lot of heat is lost through your head.
A dry sleeping bag - Have a dry sleeping bag. A damp sleeping bag is uncomfortable and draws heat from your body. Moisture reduces loft and the insulating effect in down sleeping bags but not so much in synthetic sleeping bags. Dry your sleeping bag out during the day if possible and keep your bag dry in a waterproof stuff sack when on the move.
A suitable sleeping bag - Having a warm sleeping bag that can handle the conditions is really important. Sleeping bags usually have temperature ratings showing comfort limit (for women), lower limit (for men), and extreme limit (to prevent hypothermia). Choose a bag that will has temperature ratings 5 to 10 degrees Celsius lower than the temperature you expect to be using it in. Having a sleeping bag that feels too warm is easier to deal with than having a bag that leaves you shivering.
A sleeping pad / mat with an appropriate R-value - Sleeping directly on cold ground sucks heat out of your body and will make you feel cold. When the temperature drops, having a proper insulation between your body and the ground is crucial. There are lots of foam sleeping mat, self-inflating pad and inflatable air pad options available. These come with and R rating of 1-10, the higher the number the more insulation and warner they will be. Generally 0-2 is ok for warm temps, 2-4 for most 3 season camping, 4-6 for temperatures around freezing and higher than that is suitable for snow. Many people use a combination of closed cell foam mat and inflatable air pad to increase insulation and the combined R value. If you are on your pad but still feeling cold you can also use spare clothing, blankets etc. to create another layer between you and the ground to improve insulation and warmth.
A sleeping bag liner – one of these offers more insulation and can add a few degrees to the warmth of your sleeping bag.
A 3-4 or 4 season tent – Check out tents for sale in NZ rated 3-4 season or 4 season which are designed for use during the harsher, colder winter months. They typically have less mesh and more fabric on the inner walls to help with warmth retention inside the tent. They may also have flaps or skirts on the outer fly that can block out cold winds. But avoid the temptation of sealing the tent up completely - ventilation is needed to prevent excessive condensation and moisture build up.
Time for bed
Warm your body up before you get into your sleeping bag - Try a few star jumps or jumping jacks or exercises to warm up the body and get into your sleeping bag nice and warm (but don’t overdo it to the point of sweating). Warmth comes from within, and any insulation from a sleeping bag will keep it there. You can also do a few sit ups in your bag to help warm yourself up and get the blood flowing again.
Eat just before you go to bed - Keep your body’s metabolism working for as long as possible by eating dinner or a snack just before going to bed. This will keep your body warmer for longer and keep you asleep for longer. Something high in protein and fat will keep your metabolism working longer.
Stay hydrated but not too much - Keep your body running smoothly by making sure you’re hydrated. You’re less likely to feel thirsty in the cold weather but too much water before bed may mean having to go out into the cold for bathroom breaks. And a full bladder also requires more energy from your body to keep that liquid warm. Go to the bathroom before bed.
A hot water bottle - Consider taking a bottle of hot water to bed to warm up the cold spots and keep you warm.
During the night
Sleep snug in your bag - Use the drawstrings on your sleeping bag to pull the hood tight around your face. Some have a strip of fabric around the back of your neck that prevents heat escaping from around your shoulders.
Don’t breathe into your sleeping bag - Breathing into your sleeping bag might seem like a good idea to warm things up but eventually all that moist air is going to make things damp. Keep your nose and mouth out of your sleeping bag to breathe.
More exercise – If you wake up cold in the night try a few sit ups to get the body warmed up again.
A snack – Again if you wake up cold during the night you can have a quick snack to get your metabolism going again.
Keep your tent ventilated - The heat from your body and moisture from your breath inside your tent at night can cause condensation and make everything in your tent slightly damp. Moisture and condensation will lead to colder temperatures inside your tent. It may sound counter-intuitive but you need to keep your tent ventilated at night to allow good airflow to prevent the build-up of condensation.
So there's some easy tips from us at Intents Outdoors on how to stay warm when trying to sleep out when camping in winter or when the nights get colder than you expected. Let us know if you've got any other good ideas to add to the list on how to keep warm at night. And yes, someone has already suggested 'working out' with a friend to generate some extra body heat.