My heart beats slowly — should I be worried?
I HAVE been wearing a heart rate monitor round my chest before and after exercise, which I have been doing two to four times a week. My heart rate went down to 36 recently, then crept back up to 52 before exercising. I have also felt a bit lightheaded. Should I get it checked out? I’m 40. Grant Burton, by email.
For most people, the heart beats at 60- 100 times per minute when it’s at rest — this is known as the sinus rhythm. It is set by the sinoatrial node, the area of the heart that generates the impulses triggering each heartbeat.
When the rate is below this, as it is sometimes in your case, this is referred to as sinus bradycardia. It is quite possible for this to happen to healthy people, such as in those who are very physically fit — a fitter heart can pump more blood with each beat, so fewer beats per minute are needed for it to do its job.
A slower heartbeat may also occur naturally during sleep.
But it’s important to recognise that sinus bradycardia can be a symptom of a number of conditions, so you should therefore get it checked out. one possibility is so- called sick sinus syndrome, where the sinoatrial node malfunctions due to disease.
There are many conditions that can have this effect, including sarcoidosis (a rare condition that causes small patches of red and swollen tissue to develop in the organs), or inflammatory heart conditions such as rheumatic fever.
An underactive thyroid can also result in a slow heart rate, because the hormone it secretes — thyroxine — influences the heart rate.
MEDICATIONS can cause bradycardia, and again there is a long list: beta blockers, opioid painkillers and chemotherapy drugs, are just some of the possibilities.
Bradycardia may also occur in patients with obstructive sleep apnoea — where the tissues of the throat relax and narrow during sleep, interrupting normal breathing.
It can also follow a stroke in some cases, or infectious conditions including Lyme disease, typhoid and dengue fever.
In most patients with sinus bradycardia there are no addditional symptoms, unless it is due to a cause such as those listed above. however, a slow heartbeat can cause feelings of lightheadedness — as you have experienced — or even fainting.
An underlying cause will probably come to light when your doctor examines your history. And if none of the above applies, the conclusion may well be that you are an athletic person in whom no further intervention is required.
however, as you are 40 you must undergo an electrocardiogram to record the exact pattern of the electrical activity of your heart and a blood test to check for an underactive thyroid and for other conditions such as silent infection.
Do see your doctor for an initial evaluation, but do not be alarmed. MY SISTER, aged 77, suffers from osteoporosis and has taken the bisphosphonate alendronic acid for ten years. You have previously said that people usually stop taking this medicine after five years. Can any damage be caused by staying on this drug?
She also takes medication for diabetes and blood pressure, and the blood thinner warfarin.
She has complained of losing her taste, often feels sick, and takes strong painkillers for back pain.
Name and address withheld. Bone is a living tissue that is constantly being broken down and then re-formed.
osteoporosis ( where bones become weaker and thinner, making them more prone to breaking) occurs when there is a long- term imbalance between these two processes.
Bisphosphonates are used to prevent and treat osteoporosis and work by inhibiting the process by which bone is broken down. They have relatively few side- effects when you take them orally, but these can be unpleasant to say the least, and I have some sympathy with your concern for your sister.
some patients experience acid reflux and inflammation of the oesophagus, though these are unusual if the tablets’ instructions are followed carefully.
There are some other even less common potential side- effects, such as low calcium levels — the risk is greater in patients who have vitamin D deficiency (vitamin D helps the body absorb and use calcium) or too little calcium in their diet.
Most doctors prescribing a bisphosphonate tablet also ask their patients to take a supplement of calcium with vitamin D.
A rare complication of bisphosphonate treatment is severe musculoskeletal pain — this can come on at any time, at the start of treatment, or later.
Even more rare is osteonecrosis of the jaw, where the jaw bone breaks down. Good dental care and hygiene minimise the risk.
Finally, I must mention the complication of atypical fracture of the femur (the thigh bone) — where the bone fractures gradually and spontaneously, without any trauma. This is the one side- effect of bisphosphonate therapy that is specific to longterm treatment, ie, treatment lasting more than seven years.
It seems paradoxical that drugs given to strengthen bone can actually cause the bone to become brittle, but it seems to be linked with over-suppression of bone turnover (the process by which the bone is broken down and re-formed).
THIS complication affects around just 50 in 100,000 people taking the drug, and it is usually preceded by pain in the groin or thigh, lasting some weeks. This is something to watch out for in your sister.
The potential benefits must be weighed up against these relatively uncommon hazards of longterm treatment.
Treatment for ten years is not unusual, even though most doctors tend to stop at five years if the patient’s bone mineral density is stable and they suffered no spontaneous spinal fractures before treatment.
however, in women at high risk of fracture the studies show there are benefits without an increased risk of adverse effects when treatment is continued for ten years.
Your sister’s doctor will no doubt consider whether it is the bisphosphonate that’s causing her symptoms. on the other hand, it may be the drug that he least wishes to stop, at least for now.
WRITE TO DR SCURR
TO CONTACT Dr Scurr with a health query, write to him at Good Health Daily Mail, 2 Derry Street, London W8 5TT or email drmartin@dailymail.co.uk — including contact details. Dr Scurr cannot enter into personal correspondence. His replies cannot apply to individual cases and should be taken in a general context. Always consult your own GP with any health worries.