Thursday, 31 December 2015

Heart Rate Monitoring: Numbers!

Heart rate monitoring, as a means of pacing activities, is without doubt a very useful tool for people with ME.  

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.


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): 

[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.


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).

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

Friday, 4 December 2015

Starting Heart Rate Monitoring for ME

 Recent developments in wearable technology for the fitness industry mean that ME patients, like me, can now easily monitor heart rate throughout the day.

Doing so is no magic cure.  However I think heart rate (HR) monitoring really helps me to recognize when I am in danger of doing more than my body can manage.

As Prof VanNess explained when he spoke in N.Ireland, the aerobic respiration pathways are broken in ME patients. So the general aim for us is to avoid all aerobic exercise. He suggested keeping HR below 110 beats per minute (bpm) as a useful starting point.

Put simply, “aerobic exercise” is any activity that raises breathing rate, and causes the heart to beat faster.  It is also the type of exercise that is recommended for the general population in order to optimize their health!

However as many people with ME know even small exertions can take a disproportionate toll on our body systems.  “Exercise”, in the conventional sense, is unhelpful at best and potentially harmful at worst.

So what can we do? On the one hand we want to keep as fit and well as we can, and on the other we want to prevent further harm caused by over-exertion.

Prof VanNess suggested that using a HR monitor would enable us to recognise when an activity was becoming a problem.  He suggested stopping mid-activity if necessary, and only continuing once HR had come back down again.

In practice this is much more difficult than it sounds!

Some monitors, like my Mio Alpha, have an alarm feature that alerts the wearer when HR goes up.  I found this helpful to learn how my body feels when HR is high, but I disliked the intrusion so intensely, that I now rarely turn the alarm on. I prefer to keep an eye on my HR by simply glancing at the read out.

At it’s simplest HR monitoring means watching for the activities that overly raise HR and then either working out how to modify the activity, or taking a decision to avoid it.  There are many little changes that can be made to activities to help keep HR low and experimenting, whilst wearing a monitor, can help you to find these tweaks.

Yet, starting with a monitor can be a bit scary, because suddenly you will now “see” all those high HR figures, that previously you didn’t ever record.

So it is worth taking a bit of time to find out what is “normal” for you.

In my experience I can get some very high HR spikes, but these fall again fairly quickly when I rest. My doctor has reassured me that so long as they fall quickly then I should not be too concerned with the momentary spikes.

More of a concern are activities that cause a sustained raised HR. Sadly for me any activity that involves any sort of excitement causes this drawn-out effect.  I’m guessing it is the effect of adrenalin.

And this is where good resting and relaxation habits can help.  Currently my favourite calming activity is listening to David Attenborough’s autobiography on Audible.  Going somewhere quiet, lying down, and just listening helps me to quiet my mind and body - and my heart rate gradually reduces as a result.

I have lots more to say on my experiences using a HR monitor, but for today I’ll end with just a couple more thoughts:

If you are just starting with a HR monitor, then I suggest that you continue to manage your activities in the manner that you already know works for you.  Don’t make any radical changes.

Treat your HR monitor as a friend to help you make adjustments to what you do, but forgive yourself when you can’t keep HR entirely within the desired parameters.  Being totally honest here - I can’t do it! However it is possible to minimize the duration of those higher HR periods and I think, maybe that is good enough.

Good luck!  


PS I’m happy to answer questions about how I use HR monitoring, however I am not able to look at other people’s data and express an opinion, so please don’t ask me, ask your doctor.  Thank you for understanding. xx

You may also find these posts interesting:

Heart Rate Monitoring Posts:
Heart Rate Monitoring: Numbers 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

Thoughts on "Exercise" and ME:
Graded Exercise Therapy? No Thank You! Sept 2015
The Exercise Catch 22! Jul 2014
ME Awareness - Why NOT Exercise? May 2014
The Dilemmas of Exercise and M.E.  Dec 2013

General Pacing Posts:
"Play-Up & Lay-Up" not "Boom & Bust" Sept 2014
Circles of Influence & ME Aug 2015
Do you STOP soon enough? March 2015
POST Emptive Rest June 2015

Useful Links elsewhere: 
Pacing By Numbers by Bruce Campbell
Exercise Testing and Using a Heart Rate Monitor by Jennifer Spotila

Tuesday, 1 December 2015


ME Awareness Posts:
Why? Just Why? May 2017
Who is responsible? August 2016
Chronic Illness & "determination to recover" July 2016
ME Mortality June 2016
Some Days - All Days? April 2016
Well Enough to Drink Coffee? May 2015
10 Things ME Patients Need NOW! March 2015
Living Death Disease?? Aug 2014
ME Awareness - Why NOT Exercise? May 2014
ME - A "Controversial" Illness!  Dec 2013

Thoughts on "Exercise" and ME:
GET out! Feb 2017
Graded Exercise Therapy? No Thank You! Sept 2015
The Exercise Catch 22! Jul 2014
ME Awareness - Why NOT Exercise? May 2014
The Dilemmas of Exercise and M.E.  Dec 2013

General Pacing Posts:
Disposable Energy May 2016
"Play-Up & Lay-Up" not "Boom & Bust" Sept 2014
Circles of Influence & ME Aug 2015
Do you STOP soon enough? March 2015
POST Emptive Rest June 2015

Heart Rate Monitoring Posts:
Heart Rate Monitoring: Numbers Dec 2015
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

Fitbit and Step Counting Posts:
Monitoring ME: Fitbit Sept 2014
Pacing for M.E. - And Using a Fitbit  Dec 2013

Some Grumbles of Mine:
I'm not just tired! March 2016
Work-Sick Divide? March 2016
What is ENOUGH? Aug 2015
Little Rant about "Positive Thinking"! Jan 2015
Cargo Cult Cures April 2015

Thoughts on Research articles:
When "auto-pilot" fails! (Re this paper on Gait Automaticity) Jan 2016

About Me:
About me & "Just ME" March 2016
The Use of Patient Blogs as a Care Resource
(My video presentation at Queens University Belfast) Sept 2015
The Me that Used to Be May 2014
Are You Tired Sally? Dec 2013

Relating to PACE Trial "fear avoidance" paper Jan 2015:
Newry & Mourne Group receive Expert Statement from Dr Jonathan Kerr Feb 2015
Prof. VanNess on recent press reports Jan 2015
Dr William Weir rejects "exercise phobia" in ME! Jan 2015
Tom Kindlon puts PACE in its place! Jan 2015

Some other posts of interest:
Dr Mark VanNess in Northern Ireland! Feb 2014
Pacing and Unpredictable Events Sept 2014
Thoughts on Travel and ME Mar 2014
Greg Crowhurst - Short-listed for Nurse of the Year! March 2015

ME Awareness Day & #May12BlogBomb:
My post for 2017: Why? Just Why? May 2017
#May12BlogBomb Link List for 2017 May 2017
#May12BlogBomb Link List for 2016 May 2016
#May12BlogBomb Link List for 2015 May 2015
#May12BlogBomb Link List for 2014 May 2014

Not all of the posts on the blog are listed.
Updated to mid May 2017