Letter: Vagal reaction to physical fitness test.
D001919:Bradycardia / Q000209:etiology*; D005080:Exercise Test / Q000009:adverse effects*; D006339:Heart Rate; D006801:Humans; D007022:Hypotension / Q000175:diagnosis / Q000209:etiology*; D005082:Physical Exertion; D011187:Posture; D012849:Sinoatrial Node / Q000098:blood supply; D014630:Vagus Nerve