I spend almost every day in the gym. I wear sports kit almost all of the time and I’m forever banging on about my diet and training. But I never have to change my kit after training because I never really sweat. The reason that I never really sweat is that my paralysed muscles don’t contract, which means they never demand extra oxygen, which means my heart rate never goes up and I don’t sweat and it’s incredibly frustrating.
But on the 14th of September everything changed. About 50 minutes into my usual 60 minutes walking in my Ekso Bionics robotic legs, something quite incredible happened. For the first time since I strapped my paralysed body into my exoskeleton in 2012 and over half a million steps ago, my heart rate reached a maximum of 166 beats per minute.
Watch Mark explain adding the heart monitor into today’s training.
The beating heart
Let me explain why this is so significant. In September 2008, a couple of months before I skied to the South Pole, I did a number of physiological tests. During one of these I ran on a treadmill and achieved a maximum heart rate of 178 beats per minute. At that time I was told that my aerobic stamina training for long distance cross-country skiing in Antarctica (mostly Simon and I training on indoor ski machines or dragging tyres behind us on a beach) should be in the range of 129 – 157 beats per minute. I was to start training at the lower end of this range and move towards the upper limit where I should feel it getting progressively harder. And, it did. At 157 beats per minute the effort wasn’t sustainable for 14 hours per day for weeks on the ice.
Below is a clip of Mark at his first South Pole training session with Simon O’Donnell in 2008.
Maximum heart rates differ depending on the person, age, fitness and on whether the test is done, for example, while running or cycling. We certainly must expect that there is a difference in maximum heart rate when the person being tested has been paralysed for 5 years and is being stimulated while walking in robotic legs. But we have no one else doing what I am doing yet to compare to!
Until we do, (and we are working on that), I am satisfied with comparing my stimulated robotic-walking heart to my heart before my body was so broken. Its beating, my body sweating through my t-shirt, my mind pushing me on, being able to embody my desire to train hard – at times I almost feel like me again.
Since the 166 beat high, I’ve managed to work out how to move between 130 and 150 beats per minute as I progress through our 60 minute training sessions. On the couple of occasions that I’ve pushed into the high 150s and low 160s, I’ve been overtired and struggled to keep my heart rate up on the following day. Using the rule of thumb of “180 beats per minute minus your age” suggested by Phil Maffetone – I should be hitting about 140 for my ‘aerobic’ training and that feels right.
Waking my paralysed body
And the reason I am able to do this now? Electrical Stimulation. It has to be. Of course, none of this experience is real until the tests are done and the scientists’ work is peer reviewed and published, but it has to be down to the electrical stimulation of my spinal cord, because nothing else has changed. In fact, if you listen to conventional wisdom about paralysis – 5 years after breaking my back, I ought to be more paralysed, less likely to experience any change for the better.
As I train now in the physiology lab or in the gym in Trinity College Dublin the scientists strategically place electrodes on the skin on my lower back over my spinal cord to deliver painless electrical stimulation. The idea is that this transforms the nerve network in my spinal cord from asleep to a highly functional state; it reminds the spinal cord of its potential. It’s powerful, human, striding potential.
Then, as I walk in my robotic legs, the scientists hope that this weight bearing, this repetition of the walking pattern while my spinal cord is in this highly functional state will jolt it from its paralysis coma. Over time, we hope that this will develop the conditions to encourage my brain to regain some voluntary control over my legs. At that point the robot can power down and let my legs do some of the work. I understand it to be like the robot is performing the same role as a parent holding a baby’s fingers and encouraging him to stand and to take some early practice steps before he even understands what he is trying to do.
Connecting the brain and body
I was just speaking at the RCSI Faculty of Sports and Exercise Medicine Conference. My slot was immediately before Professor Tim Noakes (author of Lore of Running, Challenging Beliefs, Real Meal Revolution, Doctor, Emeritus Professor, runner and low carbohydrate diet proponent). I was in early to test my videos and headed up to the reception area for a coffee where Tim was sitting and unfortunately for him I bombarded him with questions about my new eating plan. In fairness it is his eating plan. Simone is cooking for us at the moment from the Real Meal Revolution book and I’ve lost a tonne of weight and feel really well.
I told him about my recent Natural Born Heroes blog and we discussed my heart rate responses during my gym and lab sessions. He told me that even though I am now hitting 166 beats per minute highs I don’t need to re-fuel with chocolate milk. And he confirmed what my 24 hour ultra runner friend and Life Style Sports Run in the Dark Coach, John O’Regan says when it comes to performance, nutrition and recovery: “Listen to the body”.
To learn more directly from Prof. Tim Noakes check out his TEDx Capetown talk below.
At the conference, Tim Noakes spoke about his central governor theory suggesting that the brain is significantly more important in our physical performances than many of us give it credit for. He believes during physical exertion at the point when we think we have given our all, it is simply a physical response to our brains telling us to take it easy rather than a physiological breakdown. He has written extensively about this and gives the example of finishing spurts in races and suggests that at a time when the muscles should be at their weakest, when our minds know that we’re on the home straight and are safe in the knowledge that we aren’t going to die, our bodies’ systems are allowed to open up and work harder.
So, it seems that not only the paralysed need to acknowledge the mind’s ability to give the heart reason for beating – to power the body to achieve its full potential. It also seems that the addition of a heart rate monitor to our training sessions in the lab is just the feedback loop I needed to encourage me to push on. The full potential of my paralysed body remains to be discovered but I believe that this week’s progress may be telling us that we can dare to try to realise it.
