Sleeping bag basics

When you buy a sleeping bag you have to make sure it is warm enough, long enough and wide enough. I am told women need a different shape of sleeping bag from men. An interesting thought, but it may be ignored for now. More to the point, it seems that wome

When you buy a sleeping bag you have to make sure it is warm enough, long enough and wide enough. I am told women need a different shape of sleeping bag from men. An interesting thought, but it may be ignored for now. More to the point, it seems that women in general need a sleeping bag which is 5C warmer than men. Not so obvious is that older folk may also need a warmer sleeping bag than men in the 20-40 age group. However, an equally significant variation is caused by the experience of the sleeper: a hardened walker or mountaineer will always seem to be far more comfortable than a complete novice. On the other hand, if you just want the bag for summer use you should not be looking at snow-rated bags.

While on the subject of warmth can I recommend being very friendly with your tent partner? There is nothing quite like snuggling right up to keep you warm. If you are lying on any reasonable sort of mat your lower side is probably warm enough. If you can add a heater all down one side, that leaves only the top and other side for heat loss. It makes the night so much more comfortable. Of course, it means you both have to turn over at the same time, but you are usually aware of when the other person turns over anyhow. It is then interesting in the morning to see where you are relative to the centre line of the tent. Who chased who in the night?

To check the size ask to try the bag out in the shop. The staff should be happy to let you try getting into one briefly, provided you have clean clothes and have taken your shoes off. If they won't, go elsewhere. Make sure your feet do not touch the end of the bag when your head is well down inside - maybe when your nose is level with the front of the opening. Make sure there is enough room that you won't be sleeping with the bag stretched tight over your knees or your backside. That will compress the down, even with ""differential cut"", and reduce the insulation. It may be necessary to readjust the bag during the night to keep all of it slack, but you get used to that. In snow conditions you may need some extra space at the foot end. More than once I have stored both my ski boots (in plastic bags of course) and my water bottle inside the foot of my sleeping bag in the snow. At least I could put the boots on the next morning, and not have instantly frozen feet from it. I have also resorted to keeping my contact lens kit in my sleeping bag sometimes after I found the poor things frozen solid one morning. If you have a warm breakfast, keep your butane lighter with you too! The hood of your bag is going to be important if you are using the bag in cold weather or in the snow, so hoods get their own section below. At this stage let's just say there should be a hood of some sort for all but summer bags used in hostels, and the hood should be of a generous size.

Most people probably know to not sleep on top of the zip, especially the slider. It can be painful, and the same goes for any toggles on the cord around the hood. You may find it a good idea to make sure there is enough room in the bag to avoid the zips and toggles, or to consider removing the toggles completely. You can always tie a slip knot instead of carrying the extra weight of a toggle.

In looking at the different designs below, keep one thing in mind. While a 'bag' is the conventional design from 1890, it is not necessarily the only design. When you sleep in a bg, all that section under you is wasted: your body weight squashed the down flat so it cannot insulate. Try sleeping on cold ground for a little while and you will appreciate the truth of this. You don't sleep in a bag at home: many/most people these days sleep under a doona.