​Cardiovascular (CV) fitness is the ability of our heart, lungs and muscles to take in, transport and utilise oxygen during exercise or any daily activities which make you breathe a little harder and pump your blood a little faster (you may have heard it referred to as cardio-respiratory fitness, stamina and aerobic fitness too).
CV activities do not refer exclusively to traditional, structured 'exercise'; any activity where your heart rate is raised for a prolonged period and you start to feel out of breath counts too.  My friends and I giggled during the personal training course when 'gardening' was used as an example of an activity which raises heart-rate and gives you a good workout; I live in the centre of a town where my gardening is limited to a couple of hanging baskets and a stone courtyard, but on mentioning this to my parents who live in the countryside they agreed wholeheartedly that it definitely provides them with a good form of exercise!   
CV activities increase the heart rate and breathing rate with the aim of increasing blood flow and delivering more oxygen to the body to produce energy.  When the pulse quickens and breathing gets deeper the cardiovascular system is working.  
Activities that will improve the efficiency of the heart, lungs and circulatory system- thereby improving CV fitness are those which use the large muscles within the body in a continuous and rhythmic way and include activities such as walking, running, swimming, cycling, rowing, dancing and aerobics classes.
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​Alongside the general population health benefits of CV activity (available to all regardless of MS status), research has shown specific benefits to people with MS (PwMS) in terms of symptom management and improved ability to complete daily activities (known as ADLs: Activities for Daily Living).   
Regular CV activity has been shown to improve:

• Balance
• Coordination
• Mobility (specifically related to walking)
• Fatigue 
• Low mood
• Anxiety
• Depression

The guidelines below were published for the general population (ie those without MS) by the UK Department for Health in 2011 but it has become accepted that as far as is reasonable these apply to PwMS too (full reference below).  It is understood that the nature of the disease and the varied symptom patterns may make any level of activity challenging, however the benefits of CV activities to health outside of our MS are huge (as detailed earlier in this blog). 
As I mentioned in the previous resistance-training blog (and labour a little on the site!) the popular adage 'no pain, no gain' simply doesn't apply when exercising with MS; you should only do what is realistic for you and only you know that: not a personal trainer, training buddy or the distance of a run or bike ride you signed up to... just YOU.     ​

​If you are a gym-goer there are lots of adaptations available for using machines like the rowing machine or arm-cycling machines - both are great CV activities.  At home - a suggestion from the MS Trust's neuro-physiotherapist Liz Betts is arm-jogging whilst watching the TV or working on balance whilst waiting for the kettle to boil.  Small consistent actions can really make a difference to your fitness.   ​

​Please don't be afraid to ask for help if you're trying to work out how to start exercising; part of the PT course discusses MS so a qualified personal trainer can help put together a plan for you - in or out of the gym.  It is important that you explain about your MS and don't be embarrassed about admitting there are things you find difficult, the emphasis here is on 'personal' training so they can put together a bespoke plan which works for you and keeps you safe: safety whilst exercising is paramount.  For specific mobility-related queries it may be best to consult a physiotherapist too.
On that note, be careful about following YouTube videos by fitness bloggers; they are qualified in their own areas but they don't know you personally: one size does not fit all in terms of exercising with a condition like MS.  From personal experience pre-diagnosis and pre- PT qualification it can be costly in terms of physio appointments to repair any damage caused by following videos with no-one to correct possible poor form.  This is part of why I keep focussing on safety with anything to do with exercise.
If you haven't exercised for some time be sure to get agreement from your GP before you start to make sure there are no other factors you need to consider first.     

A quick word on terminology
This relatively recent upsurge in interest around the gut has inevitably piqued interest in the popular press and has muddied the water somewhat in terms of what exactly is being talked about.  I have seen the terms 'microbiota' and 'microbiome' used seemingly interchangeably in some popular press so in the interest of clarity:

• Microbiota: the collection of microbes within a specific anatomical niche (eg the lungs,genitals or gut).  Over 70% of microbes (bacteria and viruses) within the body's total microbiota reside within the gut.   
• Microbiome: all the genes derived from microbial processes occurring within the microbiota

This is not a hugely important point for the rest of this blog but having seen the terms applied rather haphazardly I felt it useful to make the initial distinction.
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The gut microbiota
​The human gut plays host to trillions of bacteria and viruses which have tremendous potential to impact various facets of our health; they contribute metabolic functions, protect against pathogens and educate the immune system.
The composition of bacteria in our gut begins in utero and continues for the first 2-3 years of life.  Recent studies have shown both short and longer-term effects on the composition of the microbiota in relation to:

• host genetics
• age
• external factors such as where and who we live with
• the use of pre- and pro-biotics
• exercise
• diet

​The intricate composition of the gut has been described as our 'secondary genome' and is as individual as our genetic make-up.  It lies in close association with with the host's (our) immune system and together plays a role in exerting  various nutritional, metabolic and immunomodulatory functions important to our overall health and wellbeing.   

Links between gut microbiota and disease
​Research into the gut microbiota to date has shown this bacteria implicated in the development of diseases including: 

• type 1 diabetes 
• irritable bowel syndrome (IBS)
• inflammatory bowel diseases (IBD)
• cardiovascular disease
• autoimmune diseases (including MS)

The observation that such a large collection of microbes (more than 70%) exist within our gut compared to other potential environments within the body makes it understandable that there are links to bowel conditions given its location and function; however when we begin to consider type 1 diabetes and autoimmune diseases there is clearly another mechanism at play.

Have you found that some of your MS symptoms can feel like they get worse in the heat?  We're told  - and might even be expecting - this to happen if we go away to a hot country on holiday (to sunbathe!), it's natural that heat an make everyone feel more tired but for many people with MS (PwMS) any activity which raises the core body temperature can bring on a temporary worsening of symptoms.  This has been shown to happen when cooking, sunbathing, taking a hot bath or shower and while taking part in aerobic exercise eg running, cycling etc.   

​What happens?
Research shows that heat sensitivity is common in MS with between 60 and 80% of PwMS reporting worsening of symptoms including a build up of fatigue, blurred vision, loss of balance or increase in cognitive symptoms such as concentration and memory when exposed to heat. 
The effect on balance, motor skills and vision can become more evident when exercising as aerobic exercise raises heart rate rapidly which in turn increases body temperature as blood is being pumped more quickly around the body and we eventually begin to sweat in an attempt to cool down..   
This can happen almost immediately or over a more prolonged exercise period; much of the research on time associated with symptom exacerbation is dependent on intensity of exercise in relation to rapid increases in temperature.  Although symptoms can be unpleasant the effects are temporary and are generally quickly reversed once body temperature returns to normal; the effects of heat do not cause permanent damage to nerves.    
From a personal perspective this decrease in function was the symptom which led to my diagnosis; it's hard to call yourself a 'fast-runner' if your leg decides not to work properly after 15 minutes or so! 
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​There is some evidence which shows that PwMS can't regulate body temperature as effectively as those without MS which may mean that core body temperature increases more quickly triggering this heat sensitivity. 
Changes in temperature affect the way our nerves function and make it more difficult for them to send and receive messages.  The fatty myelin coating surrounding nerves encourages effective transmission of nerve impulses (messages) from parts of the body to the CNS; as you know, in MS the myelin costing is damaged meaning that the nerves are more exposed and less protected making it more difficult to transmit accurate messages.  Myelin is also responsible for protecting the nerves from changes in temperature so where our myelin had been damaged we are less able to manage changes in temperature.
This process is not fully understood but recent research has shown that increases of only 0.5 degree Celsius can bring about an increase in symptoms. It is also possible that MS lesions can occur in areas of the brain responsible for temperature control and regulation thus making it more difficult to keep cool. 
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Why 'Uhthoff's Phenomenon'?
Ever the (inquisitive, nosy) scientist, I was curious about this term as soon as it was mentioned to me and was indeed the first indication that anything was wrong; so I set about 'doing some research'...
Early on, it was mentioned to me when explaining the condition, that as recently as 1983 one of the tests for MS was to immerse a patent into a hot bath for 10-15 minutes and see what happened!  In 1890 Professor Uhthoff noticed the transient worsening of MS symptoms once patents were immersed in the hot water.  The key symptom assessed initially was visual and how the optic nerve was affected by increases in heat (optic neuritis).  This finding lead to the early advice to PwMS not to undertake exercise for fear of worsening symptoms.  This lead to conservative advice in regard to rehabilitative exercises and resulted in subsequent deconditioning of patients through lack of exercise (do you remember last week's blog on resistance exercise in maintaining muscle strength?.  A real example of 'use it or lose it').
It wasn't until 1961 that this finding was given his name and what we commonly refer to now as 'Uhthoff's Phenomenon'. 
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​What can we do to manage heat sensitivity whilst exercising?
The research provides some practical tips to manage the heat:

• Staying well hydrated helps you to manage body temperature so always take a water bottle when exercising and keep sipping it
• it is important not to restrict water intake in an attempt to manage MS bladder symptoms as it can affect your ability to naturally cool yourself by sweating
• I like to keep a half-full bottle of water in the freezer to top up in the gym which keeps the water nice and cold 
• Cooling vests and scarves are available to help too
• Pre-cooling by taking a cold bath or shower before exercise can help allow you to exercise for longer
• You can break your workout into several smaller chunks with adequate 'cooling' breaks in between

There are also tips from the MS Trust and myself for managing heat during exercise on my site 'Tips for exercising with MS' page.
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A word for the girls...
Whilst this blog focusses on the effects of heat in relation to exercise, women are naturally more susceptible to changes in body temperature than men as a result of hormone-induced processes including menstruation and pregnancy; both of which naturally increase your core body temperature.  
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​Although worsening of symptoms has most commonly been reported in the heat, some people find that decreases in temperature have a similar effect.  As is widely reported 'no two people experience their MS in the same way'.  

​Temperature sensitivity is an irritating symptom which can be difficult to get away from if you are badly affected.  I've provided a few tips above and there are more on the website.  Exercise is an important part of helping to manage this disease so as far as you are able, it is worth trying to find a solution which works for you.

​As always, the last word from me...
Do let me know if you have found this post helpful. Send me an email: [email protected];
send me a tweet [@healthylifems] (or use icons below)
​or send me a message through the
contact page on the website, I'd love to know what you
think.
Diana xx

​The idea that antioxidants could be helpful in limiting the damage that MS causes in the central nervous system (CNS)  has been suggested by some researchers exploring the action of oxidants (or free radicals) on disease.This suggestion may seem a little far-fetched on the surface until we consider that antioxidants have been shown to help protect the body against heart disease and some cancers; so it's a relatively short jump - once we understand how oxidants can damage the body - to the idea that they could be helpful in limiting damage in MS.  
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Oxidants are highly reactive chemicals which bind to - and change - the structure (and therefore function) of specific structural components of the body.  Essential fatty acids (EFAs) are of particular interest for us with MS as they form much of the structure of cell membranes, myelin and DNA, and are highly vulnerable to damage from oxidants through an oxidation process.  
Oxidants have therefore been suggested to attack the EFAs within the CNS which may be responsible in part for the damage caused in MS.      
Oxidants are found in many every-day items including alcohol, tobacco smoke, fried foods, pesticides and air pollution; by their very nature it is difficult (even impossible) to avoid them so some research has focussed now on how we can protect ourselves and theoretically limit the damage caused by oxidants.  
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​Vitamin A is responsible for:

• Maintaining retinal health (vision)
• Stimulating gastric juices for protein digestion
• Vital roles in bone building
• Protecting against degenerative damage and damage from pollution

Vitamin A is found in :

• Pasture-reared eggs
• Seafood
• Cod liver oil
• Liver and other organ meats

Vitamin E is responsible for:

• Aiding in blood circulation
• Helping with tissue repair and healing
• Maintaining structural integrity of cells
• Slowing ageing process
• Helps to protect against cancer and heart disease

Vitamin E is found in:

• Wholegrains
• Raw nuts and seeds
• Dark green leafy vegetables (eg kale, spinach)
• Organ meats
• Unrefined vegetable oils

​2. Water-soluble vitamins
Water-soluble vitamin cannot be stored in the body in any great quantity so much be consumed as part of the diet on a daily basis.

A word of caution; individual vitamins and minerals are a very important part of a healthy diet however it's important to remember that we eat a varied diet made up of multiple combinations of different foods; so whilst these vitamins are key to the various important processes be mindful of not excluding other important vitamins and nutrients too.
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​One thing that we do know about general health, regardless of their role in MS, is that antioxidants are important in the specific functioning of the body and the prevention of certain other diseases mentioned above: some cancers and coronary heart disease.  The advice about the consumption of foods rich in dietary antioxidants underpins the UK Department of Health's '5-a day' message to consume at least five portions of fruit and vegetables per day for general health and wellbeing, so regardless of whether research in the future does show antioxidants to be beneficial as a treatment (or partial treatment) for MS it is important that we all, regardless of our MS, consume a varied diet with a selection of different fruits and vegetables each day.
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A helpful piece of advice given by many dietitians is to make sure that we 'eat the rainbow' ie eat a variety of multi-coloured fruits and vegetables each day to maximise vitamin and mineral intake.  This image taken from the British Heart Foundation illustrates this advice nicely although they are quick to point out that overall daily intake of fruit and vegetables is more important  than focussing on the range of colours, but I think it is a helpful reminder when preparing meals to think to yourself 'if there is enough colour on my plate'?  ​
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