The first chill winds of autumn and colourful changes of fall are signals to prepare for winter. As you change to winter tires, check out the furnace and mulch tender garden plants, also keep in mind what your body needs to keep you healthy during the cold months ahead.

Winter seems to conspire against us keeping our health resolutions. The short, cold days make us want to hunker down indoors; the flurry of fall activities and holiday preparations may scotch or interrupt exercise regimes and healthy eating plans. But winter is when we need to be healthiest, when risk of catching colds and flu is highest.

The older you are, the more important it is to enter winter as healthy as possible. Physical changes from aging leave the immune system less efficient, less able to fight off infections and less capable of handling multiple challenges.

The ability to regulate body temperature wanes with age. In a heat or cold snap, it takes nearly twice as long for core temperature to return to normal after age 70. This puts the elderly at particular risk of hypothermia. Signs of low body temperature include drowsiness, forgetfulness, weak pulse, slow heartbeat, slow and shallow breathing. While research has shown cold exposure does not increase risk of catching colds, most of that research was done on young people. Older people produce fewer new immune T-cells, which recognize novel threats and call out the infection-fighting army.

Recent research has found T-cells are involved in sensing core temperature changes and signalling other immune cells to turn on. The fewer the number of T-cells, the lower the ability to combat new health threats. It’s thought this is one reason vaccines don’t work as well in older people.

Unlike adolescence, where bodily changes happen to everyone at roughly the same age, the changes with aging happen over decades. And because they can be affected by illnesses, stressors and lifestyle choices, those changes affect everyone differently and at a pace unique to each of us.

Changes to blood vessels, airways and internal organs slow down movement of oxygen and nutrients into cells and removal of wastes. Hormone production changes, metabolism is slower. This all hampers healing. Regardless of age, winter health tune-ups make sense.

Stay warm and dry, advises the Healthy Aging Partnership www.4elders.org. Wear a hat and scarf outdoors to prevent heat loss through the head. Dress in layers, an inner layer to wick moisture away from the body, a warmth-trapping middle layer and a weatherproof outer layer to handle what Mother Nature throws your way.

If you plan to shovel the walk or just take a winter walk, warm up properly, proceed slowly and take breaks. The Canadian Centre for Activity and Aging at Western University in London, Ont., notes heart attack risk rises in winter, due in part to increased blood clotting and decreased blood vessel diameter. High blood pressure also worsens with the cold.

Do get some exercise. Check out the Canadian Activity Guidelines for older adults (www.csept.ca) to learn how much exercise you need and which activities might suit you best (or annoy you the least). People who exercise report fewer colds. Moderate exercise temporarily boosts the immune system, so regular exercise gives a regular boost, thus increasing the body’s infection-fighting ability.

Just can’t force yourself to exercise? Turn television from nemesis to ally by lifting weights while watching (unopened cans of soup are a handy size, shape and weight), or get active during commercials. Fit Watch (www.fitwatch.com) offers tips for a couch potato workout.

Wash your hands frequently, keep them away from your mouth and eyes and sneeze into the crook of your arm. When it’s cold out, people tend to cluster indoors, concentrating flu and cold bugs. The Public Health Agency of Canada suggests using disinfectants on shared surfaces—doorknobs, light switches, telephones, keyboards, etc.

Get the annual flu shot, especially if you are a senior, or come into contact with someone elderly or with lowered immunity. HealthLink BC advises seniors to get their flu shots and pneumonia vaccinations as early in the season as possible, to allow time for immunity to build up.

Eat to keep healthy. Today’s Dietitian (http://www.todaysdietitian) notes that lack of sunlight and Vitamin D results in a drop of serotonin, causing depression and increasing food cravings—and generally not for spinach, broccoli and bean sprouts, but for immunity-challenging starches, sugars and alcohol. It advises supplementing with Vitamin D, eating more fish and including a variety of colourful fruits and veggies every day—buy frozen when favourites are out of season.

If you do get sick, stay home to prevent spread of the virus.

Odd Body Fact

Our bodies are very good—if not as fast as we’d like—at fighting winter colds and flu. A runny nose, sore throat and cough are all signs your immune system is working hard at fighting one of the more than 200 different cold viruses, or this year’s flu strain.

Mucous is the body’s first internal line of defence, protecting cell surfaces. One reason colds are more plentiful in winter is that cold air holds less moisture. Mucous membranes dry out, making it easier for bacteria and viruses to invade cells in the nose and throat, where they hijack the reproductive machinery and start replicating themselves. So, a humidifier might be good insurance.

The human body responds quickly to an invasion. Mucous production ramps up to capture viruses; sneezes and coughs expel them. The body produces more infection-fighting white blood cells and sends them to the site of infection, where they battle the invader, and in the process inflame blood vessels, adding to sore throats, swelling and blocking up the nose and turning the mucous from clear to yellow or green.

If this is the second time this particular strain of virus has invaded, the body will quickly ramp up production of antibodies used to defeat it in the last battle; fighting a new virus takes longer as the body has to first develop a new antigen, then ramp up production—a process that can take a week or more. This is one reason some colds seem to hang on longer than others.