Staying warm involves a combination of factors including insulation (clothes, sleeping bags, quilts, etc.), generating body heat from consumption of food (calories), physical activity and external heat sources. The focus of this article will be on staying warm while sleeping in a hammock so the physical activity contribution will be minimal, unless you’re a really restless sleeper. Further, everyone’s metabolic rate is different. Some people are warmer (or colder) sleepers than others. There is no one size fits all solution to the problem of saying warm. Each person will have to apply the principles and ideas discussed in this article to their own situation.
Before going out on a backpacking trip, check the weather forecast. It is important to know what kind of weather to expect in order to guide the selection of the equipment and clothing you might need during the course of the outing. Generally we try to carry sufficient protection for 10 degrees harsher than the forecast conditions. Call that our safety margin.
If you want to stay warm – Eat, eat, eat! You’ve got to stoke the furnace. Pay attention to the types of food you bring. You need to restore the calories you burn during the day while hiking plus have plenty of remaining calories to burn while sleeping. Eat three good meals during the day and snack regularly between meals. Plan for a snack before going to bed. A snack consisting of a slow digesting food will last longer while you sleep. Hard cheese is a good option.
Slow your pace before you stop for the evening. Hike yourself dry. Don’t get stuck in the position of settling into camp with wet clothes on. Always have a dry set of clothes for the evening. This doesn’t mean carry a second set of hiking clothes. Change into dry socks, fleece long johns, and a dry t-shirt, or a fleece shirt. Whatever you’ve planned as your dry evening wear or sleeping clothes.
Remember, heat tends to escape most readily from your extremities. Therefore these are the areas to address first when trying to regulate your temperature. The balaclava is a staple in our pack and is almost always used when sleeping. An extra pair of socks, down booties, or down sleeves worn as sleep socks work for your feet and either socks or a pair of glove liners work for your hands.
For hammock hangers, keeping warm is a two plane issue. Most tend to focus on the bottom because it is the problem that is least likely to have been solved. The top, however, is the major warmth factor once bottom insulation is at least minimally provided. When cooler temperatures than your gear protects to are expected, you need to add layers or change quilts or bags just like a ground sleeper.
The Nest, Mount Washington 3, Hudson River and Sierra Sniveller quilts are baffled and filled with 800+ down to a thickness of 2.5 inches. Generally, this suggests a comfort range of around 20 degrees.
We have used the three season set in temperatures below 20 degrees. We slept comfortably in wool long underwear and balaclavas. Usually we start to bed with wool socks but remove them after 10 minutes or so. Be aware that nylon not in contact with you is cool to cold to touch, shifting around you will notice cold nylon – it will warm quickly.
Sleeping in wool long underwear and clean dry socks has a major impact on extending the temperature range of your sleep system. A word on wool long underwear, since we normally don’t carry spare pants or a spare t-shirt . The wool base layer is in the pack for two reasons: first to sleep in and second as our emergency clothes. They provide a warm close micro-climate next to the body.
Other routine supplements are the fleece Balaclava, wool glove liners (summer) and convertible fleece mitten/gloves (winter). It is rare to wear the gloves, but they are there for the totally unexpected temperature drop.
Ok, you have eaten well, you have put on a comfortable base layer. Consider these options.
If you are still carrying a pad use it. In addition to the standard mode in the hammock, the pad can be placed between the hammock and the under quilt. Both work well. Between the Hammock and under quilt is more comfortable. Additionally, it will allow better dispersion of non-sensible sweat so that you are not in the damp pool of sweat as when directly on a non-breathable pad.
To summarize each person will have a different metabolic rate. We sleep “neutral to warm” as opposed to “cold sleepers”. The following is our reference guide, you probable will want to adjust from it. It is intended as a starting point.
Open the “windows” and no top cover (See “Nesting Tricks of an Old Coot” article)
Open the windows, top quilt without footbox formed
Close windows, top quilt with or without footbox
Top quilt in footbox configuration and balaclava
Top quilt with footbox, silk weight long underwear top and bottom, balaclava, possibly wool socks
All of above, plus gloves, Shake down of the under quilt to the center areas before retiring, consider extra clothing options available
A Winter Nest, Mount Washington 4, or Old Rag Mountain on the bottom. An Old Rag Mountain or High Sierra Sniveller quilt on top, winter weight long underwear top and bottom, balaclava and wool or fleece watch cap, wool socks or down booties
As above, add gloves, consider wool socks and down booties, consider second fleece shirt and or breathable wind breaker
* Alternatively shift to a warmer under quilt such as the Mt Washington