At its simplest, it is a means of avoiding activities that elevate heart rate (HR) into the aerobic exercise zone.
Does the word "aerobic" conjure up thoughts of lycra, leg-warmers and some rather Eighties work-out routines? Maybe you think that being so ill, means that there is little risk of you entering the "aerobic exercise zone"? Well think again. All is not what it seems for people with ME.
In this post I am going to explore the various means of calculating optimal HR numbers, and then share a few of my own thoughts on using these calculated numbers in real life.
THE NUMBERS:
Maximum Heart Rate (HRmax)
Exercise recommendations for ME are generally based on limiting HR to a percentage of each individual's HRmax - which is the theoretical maximum rate a healthy individual's heart can work at, before physical damage occurs.
The simplest method of calculating your age-related theoretical maximum is by subtracting your age from 220. The result is your estimated number of beats per minute (bpm) at HRmax.
220 - [your age] = HRmax (for me: 220 - 52 = 168bpm)
Apparently other calculations (1) are now regarded as more accurate, but it seems that this simple calculation still remains the most used.
HRmax can then be used to calculate a Personal HR Limit:
There is now good evidence (2) that ME patients cannot ramp up their energy production systems normally. Consequently, people with ME should try to avoid spending time with their HR elevated into the aerobic zone. It is generally accepted that aerobic exercise is achieved when exercising with a HR of 60% of HRmax or above, and so keeping below this level has been suggested by various ME specialists.
Calculating 60% of HRmax (My Personal HR Limit):
The NICE guidelines for ME (3) suggest using a HR monitor during periods of "exercise", however they are more generous with their upper limit, suggesting 70% of HRmax as the number to remain below. I wrote a blog post about this, because it seemed to me that doctors are ignoring HR monitoring advice altogether, and that this higher limit is better than no limit at all.
A Two Day CPET Test can be used to make more precise individual HR recommendations. Unfortunately the test itself is not without risk for ME patients, because it involves two periods on an exercise bike. However the test does show clear differences between ME patients and de-conditioned controls (a possible biomarker?) and can also be useful for proving disability(2).
Whatever number is used, the lifestyle restrictions imposed by this method of pacing are significant.
LIVING WITHIN THE NUMBERS: SOME THOUGHTS.
Life Adjustments:
I glance at my HR readout every couple of minutes whilst I am active. If it is raised above 100 I then adjust or stop what I am doing until it drops again. This means most tasks take longer to accomplish because of the rest breaks, but I am convinced that doing so helps me to avoid the worst of the post exertional effects a couple of days later. However I'm not always perfect as chatting raises my HR, and socially I'm not comfortable with breaking off a conversation immediately my HR spikes. I also can't always control exactly what happens when I'm away from home.
Keeping a Record:
I use an app called Endomondo (4) on my phone to collate data from my HR monitor. This lets me see how long I spend above 100bpm each day. This can vary each day from only a few minutes (when things are really good) up to several hours (when I had a urine infection and my HR went bonkers).
Endomondo:
A screen shot from my Endomondo account online taken just now looks like this. (My labels added)
I have changed the boundaries that Endomondo sets for the various zones so that they fall on multiples of 20bpm. (Therefore the zone names shown are not correct.) I can see here that my HR is averaging a little bit higher than normal, which is hardly surprising as it is the holiday period, but the pattern is not unusual for me.
Obeying Exact Numbers?
So here's a thing. If you look at how my heart rate changes through the day you can see that it spikes up quite quickly, but also that it can drop quickly. For this reason, it may not matter what precise number I use as my upper HR limit, because in truth my heart rate changes so quickly that it would shoot past all those exact numbers anyway. More important, in my view, is to attempt to control were heart rate settles for any length of time, and to try to keep that low. I also watch where my average HR for each day falls.
Knowing when to pull back:
Tonight it is New Year's Eve. I had an invitation to go out, but I'm not going. I know that were I to be out in company tonight my HR would spike easily, and that it would not drop as quickly as usual either. The decision to stay in was not just based on today's higher than usual HR data, but also on the fact that yesterday was a busier than normal day - meaning today is a day to be ultra cautious no matter how I actually "feel".
"Dangerously Okay!"
This phrase was used by a good friend of mine recently to describe what happens when adrenalin masks our symptoms and tricks us into believing we are more "well" than we really are. I find that this can sometimes happen to me in the 36 hours after a fun event. In fact, during this day-after period my HR may actually be deceptively low - so even HR is not always an accurate measure of well-being. For this reason, I always try to ensure I have a full two days quiet time after any slightly more active day. To be sure, to be sure! ;)
On Balance:
Heart rate monitoring is an incredibly useful way of monitoring activities in the moment,and regulating them to cause minimum damage. However, I think using HR data for pacing is slightly more of an art, than an absolute science. If I were to stick strictly to keeping my HR below 101bpm at all times, I would never leave my bed. However I know I can spend some short periods each day with my HR above this number and still avoid post exertional effects. Thus I think the numbers need to be read within the context of each individual's own experience.
Looking forwards:
I admit I'm fascinated by numbers, so over the past year (& more) I've been collating much of my daily data into a large Excel spreadsheet. Using that data I've created some pretty graphs whilst looking for patterns in the data.... So - Next Year - I hope to share some of those graphs and my musings about what they might mean.
Further Information:
1)Wikipedia on HRmax
2) Workwell paper describing use of 2 Day CPET test for ME (CFS)
3) NICE Guideline for ME: [CG53]
4) Endomondo (I pay a small monthly premium for the version I use).
Other HR posts on Just ME:
Starting Heart Rate Monitoring for ME Dec 2015
Heart Rate Monitoring & NICE Guideline for ME Nov 2015
Rhythm+ and Endomondo: HR monitoring for ME Aug 2014
A few notes on using a HR Monitor for Pacing Feb 2014
Calculating 60% of HRmax (My Personal HR Limit):
[Your HRmax] x 0.6 = 60% HRmax (for me: 168 x 0.6 = 101bpm)
It is thought that if ME patients can keep their heart rate below this level, that this avoids doing further damage to their already compromised health. Less ongoing damage, in theory means more opportunities for the body to heal itself. However the reality of living within this self-imposed limitation is no easy task - more thoughts on that below.
Other recommendations on Limiting HR for ME:
The NICE guidelines for ME (3) suggest using a HR monitor during periods of "exercise", however they are more generous with their upper limit, suggesting 70% of HRmax as the number to remain below. I wrote a blog post about this, because it seemed to me that doctors are ignoring HR monitoring advice altogether, and that this higher limit is better than no limit at all.
A Two Day CPET Test can be used to make more precise individual HR recommendations. Unfortunately the test itself is not without risk for ME patients, because it involves two periods on an exercise bike. However the test does show clear differences between ME patients and de-conditioned controls (a possible biomarker?) and can also be useful for proving disability(2).
Whatever number is used, the lifestyle restrictions imposed by this method of pacing are significant.
LIVING WITHIN THE NUMBERS: SOME THOUGHTS.
Using an Alarm:
I have been wearing a HR monitor daily for over a year now. At first I used the alarm feature to warn me every time my HR exceeded 100bpm. Doing so was certainly a useful exercise to help me learn what elevates HR, but ultimately I found it so intensely irritating that I now have it permanently turned off. However, I know others who find it helpful, so I guess it is a personal choice.
Life Adjustments:
I glance at my HR readout every couple of minutes whilst I am active. If it is raised above 100 I then adjust or stop what I am doing until it drops again. This means most tasks take longer to accomplish because of the rest breaks, but I am convinced that doing so helps me to avoid the worst of the post exertional effects a couple of days later. However I'm not always perfect as chatting raises my HR, and socially I'm not comfortable with breaking off a conversation immediately my HR spikes. I also can't always control exactly what happens when I'm away from home.
Keeping a Record:
I use an app called Endomondo (4) on my phone to collate data from my HR monitor. This lets me see how long I spend above 100bpm each day. This can vary each day from only a few minutes (when things are really good) up to several hours (when I had a urine infection and my HR went bonkers).
Endomondo:
A screen shot from my Endomondo account online taken just now looks like this. (My labels added)
I have changed the boundaries that Endomondo sets for the various zones so that they fall on multiples of 20bpm. (Therefore the zone names shown are not correct.) I can see here that my HR is averaging a little bit higher than normal, which is hardly surprising as it is the holiday period, but the pattern is not unusual for me.
Obeying Exact Numbers?
So here's a thing. If you look at how my heart rate changes through the day you can see that it spikes up quite quickly, but also that it can drop quickly. For this reason, it may not matter what precise number I use as my upper HR limit, because in truth my heart rate changes so quickly that it would shoot past all those exact numbers anyway. More important, in my view, is to attempt to control were heart rate settles for any length of time, and to try to keep that low. I also watch where my average HR for each day falls.
Knowing when to pull back:
Tonight it is New Year's Eve. I had an invitation to go out, but I'm not going. I know that were I to be out in company tonight my HR would spike easily, and that it would not drop as quickly as usual either. The decision to stay in was not just based on today's higher than usual HR data, but also on the fact that yesterday was a busier than normal day - meaning today is a day to be ultra cautious no matter how I actually "feel".
"Dangerously Okay!"
This phrase was used by a good friend of mine recently to describe what happens when adrenalin masks our symptoms and tricks us into believing we are more "well" than we really are. I find that this can sometimes happen to me in the 36 hours after a fun event. In fact, during this day-after period my HR may actually be deceptively low - so even HR is not always an accurate measure of well-being. For this reason, I always try to ensure I have a full two days quiet time after any slightly more active day. To be sure, to be sure! ;)
On Balance:
Heart rate monitoring is an incredibly useful way of monitoring activities in the moment,and regulating them to cause minimum damage. However, I think using HR data for pacing is slightly more of an art, than an absolute science. If I were to stick strictly to keeping my HR below 101bpm at all times, I would never leave my bed. However I know I can spend some short periods each day with my HR above this number and still avoid post exertional effects. Thus I think the numbers need to be read within the context of each individual's own experience.
Looking forwards:
I admit I'm fascinated by numbers, so over the past year (& more) I've been collating much of my daily data into a large Excel spreadsheet. Using that data I've created some pretty graphs whilst looking for patterns in the data.... So - Next Year - I hope to share some of those graphs and my musings about what they might mean.
Let's hope 2016 is a big year for medical breakthroughs for ME....
Happy New Year!
***
Further Information:
1)Wikipedia on HRmax
2) Workwell paper describing use of 2 Day CPET test for ME (CFS)
3) NICE Guideline for ME: [CG53]
4) Endomondo (I pay a small monthly premium for the version I use).
Other HR posts on Just ME:
Starting Heart Rate Monitoring for ME Dec 2015
Heart Rate Monitoring & NICE Guideline for ME Nov 2015
Rhythm+ and Endomondo: HR monitoring for ME Aug 2014
A few notes on using a HR Monitor for Pacing Feb 2014
