It’s tough to
exercise in the cold weather, and certainly one of the most frustrating things
is that you can pull muscles. You can also put extra pressure on the chest. When
you’re in the cold, the blood vessels that go to the heart actually can clamp
down, and when they clamp down they can have decreased oxygen supply to the
heart. With that decrease of oxygen can come chest tightness and situations
resolving and leading into a heart attack. The other problem of course is if
you don’t warm up properly, and you don’t stretch out, you can also pull
hamstrings and other muscles and tendons.