Q I have been running for about five years and completed three marathons. When not in marathon mode I run 5-6 kilometres three days a week with a long run of 12 kilometres. I’ve noticed that I always feel better after the eight-kilometre mark. My heart rate and breathing settle and my muscles stop complaining. My body settles into a rhythm and the running feels very natural. My speed usually increases as well. It’s like I’m finally warmed up or maybe my body has given up complaining and just decided to go with it. Can you help me understand this? Is there a reason for this beyond just endorphins? – BILL
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A Your story is concerning and probably deserves a visit to your physician. You could be describing a variant of warm-up angina. Warm-up angina was first described in the 1800s and is a potential marker for coronary artery disease with restriction of blood flow. Basically warm up angina describes exercise-induced ischemia that improves after a period of exercise with brief rest or reduced intensity, leaving a runner (or other exerciser) feeling better with renewed energy and able to exercise at full capacity without symptoms. It is usually associated with moderate or greater intensity exercise, rather than low intensity running.
While the exact mechanism for this phenomenon is not known, it is a reason to get tested. If you have warm-up angina, there is likely some reduced blood flow to an area of the heart that is “relieved” after a period of exercise. Once blood flow is restored, full exercise is comfortable because the ischemia is resolved. However, during the period of reduced blood flow and regional low oxygen levels, the heart is at greater risk for an arrhythmia and sudden cardiac arrest is possible. I had a patient who had this, refused evaluation, collapsed at several races, refused help at the races, and eventually had a fatal arrest during a race. This was difficult for family, friends, fellow racers, and the race staff.
I would suggest you meet with your physician and consider a stress test that mimics or reproduces the running intensity that gives you the symptoms. This should be combined with an imaging study also to look for abnormal heart wall motion or areas of ischemia.
