Exercise is an excellent tool for alleviating anxiety and improving physical symptoms of panic and stress. “Studies show that it is very effective at reducing fatigue, improving alertness and concentration, and at enhancing overall cognitive function” (www.adaa.org). Even 5-10 minutes of light walking daily can produce great physical and mental benefits. Exercise reduces stress hormones and produces endorphins, which elevate mood, act as natural painkillers, and make it easier to sleep. Like meditation, exercise costs nothing and produces no harmful side-effects, and brings positive changes that can last for hours afterward and accumulate to create long-term benefits for body and mind.
Here is an excellent article from the ADAA on the stress- and anxiety-reducing benefits of exercise:
And another, from the Mayo Clinic:
A PsychCentral article about the ways in which exercise can reduce fear of panic attacks: