I woke up this morning with good intentions of working up a sweat at the gym, threw on my gym clothes- heart rate monitor strapped on-, ready to go and then proceeded to lay down on my couch to "meditate", I woke up two hours later, looked at my heart rate monitor and it reads "42 BPM".
Kind of just laid there and freaked out for a second and then got my heart rate to it's normal range. I'm thinking it's just a sign of low blood pressure, due to to some adrenal gland fatigue from a crazy training schedule.
asked byBen_Joven (1669)
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on April 28, 2012
at 12:14 AM
As foreveryoung says, if you are fit, all should be fine. You may have something described as Athletic heart syndrome (AHS). Syndrome sounds a bit iffy right?...but there's no need to worry.
Athletes tend to have lower resting pulses because they have bigger hearts which pump a greater volume of blood per stroke (stroke volume) . The heart will generally get bigger (& stronger) with exercise. This change will reverse on returning to a more sedentary lifestyle. http://en.wikipedia.org/wiki/Athletic_heart_syndrome
With your low blood pressure query; are you feeling dizzy when you stand up (from seated position) or like you may black out? That's a sign of low blood pressure, a lack of blood (oxygen) getting to the brain quick enough. http://en.wikipedia.org/wiki/Orthostatic_hypotension. If not then your blood pressure is most likely fine.
2nd Edit (09May2012): from what i can tell the following pov for a slow heart beat relates more to endurance runners, but interesting anyway:
Source: An Interview With Dr. Raymond Peat
Mary Shomon: You feel that excessive aerobic exercise can be a cause of hypothyroidism. Can you explain this further? How much is too much?
Dr. Ray Peat: I'm not sure who introduced the term "aerobic" to describe the state of anaerobic metabolism that develops during stressful exercise, but it has had many harmful repercussions. In experiments, T3 production is stopped very quickly by even "sub-aerobic" exercise, probably becaue of the combination of a decrease of blood glucose and an increase in free fatty acids. In a healthy person, rest will tend to restore the normal level of T3, but there is evidence that even very good athletes remain in a hypothyroid state even at rest. A chronic increase of lactic acid and cortisol indicates that something is wrong. The "slender muscles" of endurance runners are signs of a catabolic state, that has been demonstrated even in the heart muscle. A slow heart beat very strongly suggests hypothyroidism. Hypothyroid people, who are likely to produce lactic acid even at rest, are especially susceptible to the harmful effects of "aerobic" exercise. The good effect some people feel from exercise is probably the result of raising the body temperature; a warm bath will do the same for people with low body temperature.
According to Peat, exercise accelerates the breakdown of thyroid hormones, resulting in a protective slowing of metabolism. ???The slow heart beat of runners is largely the result of this adaptive hypothyroidism.???
1st Edit: this may be of interest as well (although not directly related to your question).
It's another athletic "syndrome" referred to as terms such as 'athlete's anemia', 'athlete's hemolysis', 'sports anemia' etc.
Here's a good article by Dr. Randy Eichner that covers it http://www.gssiweb.com/Article_Detail.aspx?articleid=276 Here's some of the text;
E. Randy Eichner, M.D.
Department of Medicine
University of Oklahoma Health
Athletes, especially endurance athletes, tend to have slightly low hemoglobin levels as judged by general population norms. Because a low blood hemoglobin concentration defines anemia, this has been called sports anemia.
But sports anemia is a misnomer because in most such athletes???especially men???the low hemoglobin level is a false anemia. The total volume of red cells in the body is normal, not low. Hemoglobin level is decreased because aerobic exercise expands the baseline plasma volume; this reduces the concentration of red cells, which contain the hemoglobin. In other words, the naturally lower hemoglobin level of an endurance athlete is a dilutional pseudoanemia.
Pseudoanemia is an adaptation to hemoconcentration that occurs during workouts. Vigorous exercise acutely reduces plasma volume by 10-20% in three ways. One, a rise in blood pressure and muscular compression of venules boost the fluid pressure inside the capillaries of the active muscles. Two, generation of lactic acid and other metabolites in muscle increases tissue osmotic pressure. These forces drive plasma fluid, but not red cells, from blood to tissues. Three, some plasma water is lost in sweat.
In response comes the release of renin, aldosterone, and vasopressin to conserve water and salt. Also, albumin is added to the blood (Nagashima et al., 2000). As a result, baseline plasma volume expands. Even a single bout of intense exercise can expand the plasma volume by 10% within 24 h (Gillen et al., 1991).
So it is common for an endurance athlete to have a hemoglobin concentration 1 g/dL or even 1.5 g/dL below "normal". Recognizing this as pseudoanemia depends on knowing the setting (aerobic training at sea level) and excluding other anemias. Plasma volume waxes and wanes quickly in concert with level of exercise, so athletes who train the most have the lowest hemoglobin levels and when daily workouts are stopped, hemoglobin level soon rises.
Pseudoanemia is key to aerobic fitness. The rise in plasma volume???plus the adaptations of "athlete's heart"???increases cardiac stroke volume. This more than compensates for the fall in hemoglobin concentration per unit of blood, so more oxygen is delivered to muscles. Result: A better athlete.
on April 27, 2012
at 11:49 PM
dude you're fine. If you're fit, it's just a sign of a wicked efficient cardiovascular system. When I rowed a lot of lightweight crew my resting heart rate was 41BPM. Now it's between 48-52. If I increase cardio significantly though, it'll drop back down again. Well, let me clarify. Your pulse should be very strong, not weak. Strong and slow is better than fast and weak.
If it were adrenal fatigue your pulse would be high because you would have high sympathetic tone.
on April 28, 2012
at 05:26 AM
Your HR is always lower after rest and if you've been laying down for a while. If you usually take yours during sitting or standing after being awake or active, don't be alarmed.
Back in the day when I was healthier, mine was taken in a physiology course. I was laying down, and it was 52. I wasn't a super athlete or anything, so if you're working out fairly intensely, I wouldn't find it surprising it was that low. I think it's perfectly healthy if you fine otherwise if you haven't had any other worrisome symptoms.
on March 11, 2013
at 05:43 AM
on November 26, 2012
at 11:27 PM
Low blood pressure and lower than regular heart rate are also symptoms of adrenal fatigue and overtraining. I used to have a 48 resting rate and while suffering with extreme adrenal fatigue it went down to 42. I also and lower blood pressure, would get dizzy when getting up suddenly, had cold hands and feet, and was unable to sleep well, to name a few things. So if you have a resting rate to compare it to, that would help. By itself 42 bpm isn't really an issue. However, If your resting heart rate is normally 50 or something greater and it suddenly dropped, that's a good warning sign. Low doesn't always necessarily mean crazy awesome shape.
on April 28, 2012
at 07:34 PM
That actually shows you are really healthy! Within a few months of starting paleo and working out more, whenever I put on my heart rate monitor in bed or while meditating it is also very low. Lance Armstrong's resting is in the high 30s. Your heart is a muscle, the larger it is the less beats needed to pump blood!
on April 28, 2012
at 05:03 AM
Fitter you are lower the HR usually, i'm 42 years old & its usually between 33-36 first thing in the morning.
Do a lot of cycling so got a good endurance level but also got a low MAX HR of only just over 160 bpm.