Do your warm-up exercises inside to give your cardiovascular system a chance to prepare for the change in climate. Begin the aerobic portion of your workout slower than you would during the summer. And if the surface is slick, consider a fast walk rather than a jog or run to ensure better footing, or run with shorter strides than you would on dry pavement. Cold-weather workouts may not be for everyone. If you have heart disease or diabetes, consult your doctor first.
Arthritics require additional time to warm up their joints.
And asthma sufferers may require a mask to help warm the air they breath. Chances are, however, that if you maintain a regular workout schedule and dress properly, your body will acclimate to the demands of cold weather with little effort. Lastly, don't panic if you feel the necessity to skip a workout when the temperature dips below your comfort level. The healthy benefits of cardiovascular exercise are lost at half the rate at which they were attained. If you work out consistently for a week, it takes 2 weeks to lose the fitness gained.