Exercising in cold weather

[runnertom]

I am a 55 year old heavy exerciser for the last 30 years (comptitive running and cycling). I was diagnosed with a blockage of the LAD and first diagonal last Feb which was successfully bypassed. (Possibly inappropriately since it was heavily collaterized, heart function was normal and my only symptom was transient shortness of breath going up multiple flights of steps or in the first 1/4 mile of running). I had none of the major risk factors, although I have subsequently discovered high homocysteine. My question: I have always heard that cold weather exercise is one of the most dangerous activities for at risk men to engage in, as evidenced by the large number of heart attacks while shoveling snow. This troubles me, as winter is my favorite time to run. Are there any guidelines I should be following this winter? I do not consider running indoors on a treadmill a viable option. I find it so boring that I will opt to do nothing rather than face that.
   A second question: After 8 months, I am still feeling measurable improvements in my performance. I cannot believe its due to getting back in shape, as I don't feel I lost that much through the surgery-was back to cycling in 6 weeks. I would like to think the improvement might be due to some reversal of my disease due to my medications (Provacol,Altace, folic acid, and B-vitamins). Any thoughts?

[CCF-M.D.-RCJ]

Runnertom,

Thanks for the post.

Q:"I have always heard that cold weather exercise is one of the most dangerous activities for at risk men to engage in..."

Exercising in cold weather produces a larger oxygen demand, and thus is more likely to precipitate ischemia (an oxygen supply- demand mismatch).  However, the basic reason that snow shoveling, or swimming in the spring, has gotten a bad rap is that out-of-shape men tax themselves by performing an activity that they did not realize was so strenuous.  The "guideline" I would recommend for a conditioned athlete is to listen to your body, paying attention to undue shortness of breath or chest discomfort.

Q:"After 8 months, I am still feeling measurable improvements in my performance ..."
I don't think that you are going to believe my answer, but heregoes.  More than likely, your peak exercise performance prior to the surgery was impacted by the blockage more than you realized.  You are now making gains because you are able to reach a higher anaerobic threshold due to the lack of ischemia.  Certainly, the medicines could be contributing as well.

Hope that helps.

[runnertom]

Doctor,
   Thank you very much for your response. I will accept the higher anaerobic threshold as plausible, but I would have thought I would have noticed that effect earlier in the recovery process. I noticed the disappearance of the transient shortness of breath fairly early on, but have only noticed the more effortless running in the last several weeks. I performed at 13.5 METs on my last stress test 4 months ago.
   Is there a less invasive and less expensive means of evaluating the status of coronary arteries than angiography for non-symptomatic persons who may be at risk? Since my shortness of breath had been with me for years, I really thought it was normal for someone my age who was doing strenuous activity. Also, it disappeared after I was warmed up, presumably from the action of the collateral circulation. I got an angiogram based on my family physician's concern about my PVCs during exercise. (The CABG did not eliminate them, so maybe it was just luck that my blockage was found).
   Through other posters on this forum and my own reading (Gould), I understand that PET scans have high sensitivity and specificity for CAD. My insurance is unwilling to pay for it as its considered experimental although there would be no question about a Cardiolite stress test that costs at least as much.

[CCF-M.D.-RCJ]

Runnertom,

Your best bet is to go by your symptoms, if possible.  Stress tests often show ischemia after bypass, perhaps from artifact, or perhaps from incomplete revascularization.  The ischemia detected, however, may or may not be clinically relevant -- all ischemia does not need to be fixed.

Good luck.

[runnertom]

Doctor,
I don't mean to belabor this exchange, but my question may have been misunderstood. I was not referring to my immediate situation. I am interested in the more general situation where an athlete may not feel particularly 100% but stress testing is negative. My blockage was discovered accidentally or maybe by doctor's intuition rather than through any hard clinical evidence pointing to the need for an angiogram.
   I am familiar with at least one other case where a competative cyclist was found to have complete LAD blockage. After negative stress testing, he got the angiogram by extensive badgering of his doctor. His only "symptom" was the fact that he could not beat his companions over a certain hill as he once did.
   I was talking last week to a cousin of about my age with similar athletic history. The occasion was the funeral of his non-athletic brother (age 56) who had passed away as the result of a heart attack. The athletic cousin had transient shortness of breath similar to mine and had also had a negative stress test. What would be a reasonable next step in the absence of more typical heart related symptoms? I doubt if most insurance companies would pay for an angiogram because you are not "king of the hill" any more or get a little winded climbing steps at age 58.

[CCF-M.D.-RCJ]

Runnertom,

I actually agree with the point that symptoms should be judged in context.  When I was a medical resident I once saw a marathon runner who presented with chief complaint of shortness of breath at the 12th mile -- she was diagnosed with sarcoidosis, a rare disorder.

So, what should someone have done if they have transient or mild shortness of breath?  It depends, and is a judgement call based on the comnfort level of the patient and physician.

The bottom line is that it's a dangerous world out there, and our diagnostic and prognostic abilities are not perfect.

[runnertom]

I am not sure how to respond to your comment. Although the thallium stress test has excellent sensitivity (will find most ischemia), it has very poor specificity. That is, it has a very large number of false positives, or problems that really do not exist. Once a person who may or may not have symptoms has a positive stress test, the only referee of whether it was a true or false positive then becomes the "gold standard" angiogram.
   The angiogram is good at finding larger blockages (>70%) that would be typically treated through surgery or angioplasty. Unfortunately, recent evidence shows that it is usually not the large older blockages that rupture and become the life threating MIs, but the younger smaller lesions that are often discounted in an angiogram and may not show significant ischemia on a thallium stress test.

[Emmaj]

Your situation is interesting to me - a few common threads! I'm 50, must be a year older than you... also have had heart attacks several and just recently a mitral valve replacement, which was my second surgery, first being a bypass. I wish I could say I ran a 15 minute mile! I'm in cardiac rehab. now and walking a 17.1 minute mile. Good luck with the valve surgery!! I wish I had a good response to you, runnertom... managed health care is not overly patient-friendly. What I used to notice with angina and exercise (before I knew it was angina and that I should stop exercising!), is that the angina would come on in the beginning of my jogging or walking while I was warming up and go away after I warmed up. I hate to admit my naivite, but I thought the "bad feeling" was simply part and parcel of warming up! ...That was back when I was new to jogging and knowledge of heart disease was just around the corner. Wish you best of luck too, RT!

[Emmaj]

ps

*I have long noticed an increase of cardiac symptoms (mainly angina) with the cooler fall weather as my body has adjusted.

*One other jogging symptom I noticed when in ignorance of my problems: I never could increase my speed... I was definitely not listening to my body -- rather, I was listening and 'heard' quite a bit, just wasn't following up...

*Given your cousin has heart disease in his family -- his brother and you, his cousin -- that would would doubtless weigh in his favor if he wanted to pursue an angiogram...

[runnertom]

I guess the statement about my cousin kind of gets to the heart (no pun intended) of the issue. For someone whose only complaint is a being a little winded going up steps with a negative stess test, the next step of an angiogram is a pretty big one, both in cost and the potential of complications. And obviously, that is where the insurance comes into play. There must be a less invasive step here and that would be the "experimental" PET scan which has the sensitivity of the thallium stress test but very low incidence of false positives. This thread has rambles somewhat from my original intent, but I think the dialogue has been useful.

[snowgoose]

I am presently one month into recovering from two bypasses.
Noticed discomfort on hard exercise but for awhile suspected it was muscular only because I had been splitting some extremely hard wood.  Flunked a stress test in an obvious way but 3 years ago passed same with flying colors.  3 years before that passed Thallium stress test with flying colors.  Stress tests are only one tool.

Certainly understand reluctance to do angiogram.  I would suggest instead for Runner Tom and others to get an Electron Beam Tomograph.  Non invasive and less radiation that a chest X-ray.  In anyone 50+ years old, will surely show blockages large and small.

As to exercise and ischemia, my intuition tells me that since we are circulating blood through all our bodies including our skin, temperature can change things considerably depending on individual make up.  Normally blood flow changes with temperature and anyone who has had heart disease, if they are honest, has to admit to some abnormality.  Maybe Runnertom can find a research group that would put some telemetery on him for outside.

Dress in layers to start warm and end up not too hot.