Biology Stack Exchange is a question and answer site for biology researchers, academics, and students. It only takes a minute to sign up.
Sign up to join this community
I'd like monitor my resting heart rate and blood pressure to see how they are affected by regular cardiovascular training and other events in life.
When should I take the measurements in order to reduce day-to-day variations? In the morning or evening? Before or after eating? Right after waking up?
Of course I'll make sure to follow good routines when measuring, but the ones I've found prescribed by hospitals don't state an appropriate time of the day.
I would be very surprised if the time of day made a difference. I've personally never heard mention of such a phenomenon in discussions with intensive care practitioners (where of course HR and BP are measured constantly). However this is only the case during rest, this paper (on horses) suggests that there is some difference in HR and BP after exercise depending on time of day.
You are right to attempt to control it however, I suppose. It doesn't matter when you take your measurements, as long as you take them at the same time each day.
I would say that one of your first suggestions of taking the measurements almost immediately after waking. Of course you would have to be relaxed as you assembled your equipment then rest for a few minutes in the posture you have chosen (this will matter) before taking the measurements but otherwise I can't see you having too great a problem.
It kind of depends. If you want to compare apples to apples, check it first thing in the morning. However, that's going to be at the lowest point. It's also important to know what your blood pressure is during the day, when you're living your normal daily life. I recommend checking fairly regularly in the morning so you'll know what your true baseline is and whether it's trending up or down, and to "spot-check" occasionally at different times of the day to see how your body is handling the normal daily stress
Actually in my research into circadian events, the hourly differences in blood pressure was the first thing that I found. Based on this, I'd state that there are hourly differences in blood pressure and cardiovascular efficiency.
Because these changes are circadian, measuring these values at the same time every day (ex: 1 hour after wake up time or 1 hour before bedtime) would reduce variation. Just be aware of your caffeine intake - it may skew the measurements.
I do not have access to the scholarly library that I used then, so the chances of finding the article are slim to none.
