Although it’s not an ‘ask me anything’ week, there was a message in my inbox from a few week’s back that I wanted to address, and some events this week jogged my mind to do so (related to my own stupidity!) I really should know better. On Tuesday, I got on my indoor bike for what I had planned to be a 45 minute zone 2 ride (I have written about zone 2 before, but in brief, it’s an easy pace, and where the most benefit is to be had in terms of long-term health benefits in a man of my age). However, the music I was listening to was good, I felt great, and within a few minutes I was going far harder than planned. By 15 minutes I was beating my PR (in terms of output). My heart rate had already hit 183 a few times. By 30 minutes however, I was struggling. The cycling term is called bonking, and it’s essentially when you hit a wall and just have no energy left. It’s a lot to do with metabolism, and your liver and muscles running out of glycogen (fuel source) to supply your body with sufficient energy to do the work. I got to the finish line, but was utterly spent. I took my electrolytes, got some carbs in quickly, but felt pretty rotten. One of my main issues, was timing. This all happened well into the evening. What would I tell a patient exercising that hard late at night? Don’t do it!
One of the main reasons for this is impact on sleep. Sleep is of the utmost importance for health, and I’ve written about it lots before. Suffice it to say, I could not get to sleep that night. Although clearly it had dropped a lot from peak, my heart rate was far too high (it’s usually about 51 and was still in the 80s) and I could hear it in my ears lying in bed. My body clock was all over the place, for such a stupid reason.
Please don’t make the same mistake I did! If you are going to do something intense, avoid doing it near bedtime, and fuel your body appropriately beforehand!
The question from a member was whether a low heart rate is as worrying as a fast one? This person wears an apple watch, and it’s certainly the case that with wearable technology, many of us are now aware of something that previously we wouldn’t have concerned ourselves with.
The answer depends a lot on circumstance. For example, a slow heart rate in a young, fit person is often not concerning, whereas it may be in an older person.
Is the slow heart rate a new problem? If a person tracks their heart rate and then notices a significant drop from baseline, that could be a concern.
I have recorded a video on the heart’s electrical system before, so do check it out if you haven’t seen it (under heart rhythm in the topics section). Essentially though, any interruption of the electrical signal flowing from top to bottom in the heart could cause the heart to beat more slowly. This could be an issue with the electrics themselves (and commonly happens as we get older) or could be influenced for example by another issue like low thyroid hormone levels, or certain medications that can slow the heart rate.
Can a slow heart rate be treated? Well, it depends whether there is a reversible cause that can be addressed, and indeed if it is actually causing a clinical problem. For example, each week I implant pacemakers into patients whose hearts have gone too slowly and they have had symptoms like a blackout, dizzy spells, or even fatigue and breathlessness.
Outside of intravenous medication in a hospital setting, there aren’t any drugs prescribed just to speed the heart rate up.
One might think that a low heart rate and low blood pressure go hand in hand. Actually that’s not always the case. Whilst a slow heart rate can cause a low blood pressure, sometimes paradoxically the body increases the blood pressure when a person has a very slow heart rate, in order to improve the blood supply to the brain. Clever!
If you have symptoms of a slow heart beat such as those described above, please do get yourself checked out. A blog like this clearly can’t provide a bespoke answer, but hopefully I’ve outlined a few points of interest for readers, and maybe it’s also reassuring to hear that even a cardiologist can still make silly mistakes with their own heart rate!