As we approach the colder months, Professor Mike Tipton from the the University of Portsmouth and Professor Hugh Montgomery from University College London have some tips and advice to help people stay warm and save money this winter.
Just stepping up and down on the bottom step of a staircase can produce and additional 200W of heat and raise body temperature in a matter of minutes. However, making heat requires fuel, so ensuring that enough energy dense foods are eaten to meet the demands of heat generation, is important.
As we get cooler, the blood vessels in our skin shut down, shunting the flow of warm blood deep beneath the insulating layers of fat which we all have. This makes the skin, especially of the extremities, uncomfortably cool, but is an effective strategy for protecting deep body temperature: 2.5cm of fat insulates to a similar degree as a 7mm thick wetsuit. But we can limit loss even further by wearing warm insulating clothing. Mountaineers and polar explorers, of course, can survive comfortably in environmental temperatures well below freezing by wearing the right clothes.
So, taking some exercise, eating well, and adding some clothing can all help us stay warm. But poverty may limit options for some, and the elderly, sick and disabled may also be more vulnerable. Some medications can lower the body’s energy production, as can some diseases. Age is sometimes associated with loss of muscle mass, which not only normally makes heat, but offers some insulation too.
Metabolic rate at rest is lower in the elderly, and frailty in any form can make it hard to exercise and generate extra heat. The elderly tend to detect and respond to cooling less well than the young. In addition, there are health hazards (for instance, the appearance of fungal mould on walls, which can worsen lung function) if houses are kept too cold. For all of these reasons, current advice is that rooms should be kept at a temperature at or above 18°C (although this may be less of an issue to the young and healthy).
So, with winter coming, what do we do to stay healthy and wealthier? We can all act and visit the frail or elderly to help them take action.
Just stepping up and down on the bottom step of a staircase can produce and additional 200W of heat and raise body temperature in a matter of minutes
Professor Mike Tipton, University of Portsmouth, Professor Hugh Montgomery, University College London
Having evolved as tropical animals, a naked resting human is most comfortable in air at 26-28°C, with a deep body temperature of 37°C and a mean skin temperature of 33°C. Humans are also homeotherms, that is they must maintain their body temperature within tightly constrained limits in order to remain alive and well. They do this biologically and behaviourally, by adjusting both their heat production or inputs, and its loss.
On average the temperature of indoor environments in high income countries has increased over the decades; reversing this trend and turning the thermostat down can result in energy savings. So, at a time when energy costs are high and unsustainable, can we use what we know about how the body works (physiology) to remain safe and comfortable in cooler indoor environments?
The biochemical reactions which go on in our bodies generate heat as a by-product: at rest, the equivalent of an 80W heater. We can generate more through physical activity: when we exercise, about 25 percent of the ‘chemical work’ we do to power our muscles actually goes to moving us, and about 75 percent is lost as heat.
Look after yourself
If chilly, and physically able, take some exercise indoors every now and again to warm up until the blood flows back into your fingers and toes (fingers should feel warm when you touch your lips).
Clothes such as woollen jumpers, down jackets, leggings and (though unfashionable to some) thermal underwear, trap millions of tiny pockets of air between material which itself doesn’t conduct heat well. The clothes don’t necessarily need to be thick, and multiple layers of more ‘ordinary’ clothing (think t-shirt, shirt, thin and then thick jumper; thin and thick socks and slippers; leggings under tracksuit bottoms or trousers) can work well for those who can’t afford expensive thermal clothing. If sitting in a chair, extra layers (a blanket or duvet) can make a big difference. At night, wearing pyjamas (or even other layers) underneath extra bedclothes will help.
Top it off
There is an old mountaineering adage, “if you want warm hands wear a hat”. Because blood flow to the skin of the scalp doesn’t shut down as well as other areas in the cold, a lot of heat can be lost through the head. It can also be lost at the neck as heat rises from underneath the clothing and escapes at the neck. So, wear a hat and neck covering (scarf/buff).
Keeping hands and feet warm
Keeping hands and feet warm makes you feel much more comfortable. A small amount of exercise that maintains deep body temperature will help maintain blood flow to the extremities. Add a hat and some gloves (they can be fingerless for dexterity), and you are even better off.
Especially if elderly, make sure that you are eating enough calories and drinking plenty. Of note, whilst eating a hot meal or drinking a hot drink are comforting, they won’t of themselves do much to keep you warm - and you can save money by avoiding the kettle and oven when it isn’t really needed.
Heating your home and saving money
Now that you are heating yourself up, you can spend a lot less on heating an entire building (your home). You might also consider the following:
Choose a core room
Heat a ‘core room’ in which an individual (or individuals) mainly reside - only heating other rooms (such as bedrooms) when they are needed.
Prevent heat loss
Use draft excluders at doors (even rolled rugs or towels can help), shut windows, and close (ideally thick) curtains to keep heat in. Ensure that heat loss around and through windows is minimised (there are ‘film and hairdryer’ methods of applying cheap temporary double glazing). Make sure that the attic (if you have one) is really well insulated.
Sort out the boiler
Make sure that it is properly lagged, and set to a lower flow temperature.
Turn the heating down
Turning the thermostat down from 21.5°C to 20.5°C can save up to 13 percent of energy costs, and there are further savings to be made by reducing the temperature to 18°C .
Keeping lights off where not needed, and using energy-efficient LED bulbs, can save money which can be spent on heating. Think about a small LED ‘spotlight’ rather than lighting the whole room.
Make a splash
A short and cooler shower saves vastly over a longer or hotter one or a bath.