“If we are facing in the right direction, all we have to do is keep on walking”.

Buddhist saying

The Obesity Paradox

According to research, obesity is to a certain extent genetically determined. The pandemic now affects a billion people and has gradually grown over the last 150 years. Interestingly, our genes have not changed over that period. So how could obesity, which is genetically determined, have appeared over a time when our genes have remained unchanged? What has changed?

Well, over 150 years ago 90% of the population lived an agricultural lifestyle. They walked to work, performed active physical work, walked home after work. Water had to be carried and clothes washed by hand. Our lifestyles were much more similar to those of our distant ancestors in that, we stood and walked for most of the day.

With the advent of industrialisation and urbanisation 50% of the world’s population moved to the cities. This figure is even higher in developed countries. Factory work became prevalent and chair-based work replaced standing just like machine operation replaced tool use. The biggest change has taken place over the last 25 years…over half the population in the developed world now sits in front of a computer for 8 hours a day. As a result of these changes, our occupational energy expenditure could have decreased by as much as 1200 kcal/day.

At home most of us have a personal computer and we spend a few more hours banking, shopping, browsing and even socialising (Facebook, Twitter, MySpace, etc)! Oh, and if we’re not sitting in front of the computer it’s probably the television…another brilliant invention that appeared in the last century. Sales of labour-saving devices like washing machines, dishwashers and cars track obesity rates and it’s estimated that mechanisation saves  around 111 kcal/day.

Obviously food has become more available (in industrialised countries) and one could assume that our intake has increased. Surprisingly, in the UK since the 1980s, energy intake seems to have decreased whereas obesity rates have doubled! Statistics in the US show that intake hasn’t changed but obesity has skyrocketed…

Here’s a quick thermodynamics refresher…when energy is added to a system it’s either used to perform work or stored…if the energy intake is greater than the energy expenditure, the excess is stored as fat…if the energy imbalance continues over several months or years it leads to obesity. It’s becoming clear that it’s the decrease in our activity that has lead to the weight gain.

How come we haven’t all been affected by this? This is where the genetics plays it’s part. Those of us that are genetically programmed to conserve energy have blossomed in this new modern environment, the rest have found other ways to replace their need for movement: walking or cycling to work, pacing about at work, getting involved in DIY at home, going to the gym or taking part in sports or active hobbies. Crucial research shows that lean sedentary people stand and walk for about 2.5 hrs/day more than obese people. If obese individuals were to stand and walk 2.5 hrs more each day it would equate to an expenditure of 350 kcal/day which is exactly the figure that was identified in a different study to determine the amount of exercise that obese people had to undertake to help weight loss.

Why should we care about obesity? Perhaps because it’s been linked to type 2 diabetes, hypertension, stroke, arthritis, sleep apnea and cancer…maybe because obesity related medical expenses are out of control and  in the US they reached $75 billion in 2003!

What’s the best way to lose weight? Is it through exercise or non-exercise activity? Or both? According to Dr Levine, the majority of people who exercise for just under 2 hours a week expend an average of about 100 kcal/day. This is a drop in the ocean compared to what it’s possible to achieve by increasing non-exercise activity. Granted, we can’t all change our jobs and become lumberjacks or tree surgeons but we can become more active both at work and at home. Our muscles are almost completely silent when seated and as a consequence, our energy expenditure is negligible…our expenditure goes up 15% when standing and doubles when ambling…purposeful walking can double or triple it! So, spending less time sitting seems to be the key to burning up more calories.

Prolonged sitting time has been linked to metabolic syndrome, type 2 diabetes, obesity and cardiovascular disease. This is thought to be the result of poor fat metabolism due to the decreased production of lipoprotein lipase in muscles when seated. Non-exercise activity reverses this process.

It appears our technological innovations have had insidious effects on our health. The antidote lies in freeing ourselves from the chair…can we afford to wait for governments and corporations to reengineer our workplaces? Probably not…we must all take responsibility for our health and those among us that have a predisposition towards energy conservation need to take active measures by simply standing and walking about more often and for longer periods during the day.

Most of the information in this post is inspired from the work of Dr James Levine, Professor in the Department of Endocrinology at the Mayo Clinic in Rochester MN

What Else Can Help Lower Blood Pressure?

Last week we discovered that exercise is very effective at decreasing high blood pressure but what else can help? For those with hypertension, you’ll be relieved to hear that there are several things you can do to decrease your blood pressure and cut down the risks of heart disease and stroke.

• Weight loss. Losing 8kg can decrease your systolic blood pressure (SBP) by 8.5mm Hg and decrease your diastolic blood pressure (DBP) by 6.5mm Hg. A man’s waist circumference should be less than 102cm (90cm for asian men) and a women’s should be less than 88cm (80cm for asian women).
• Diet. A small reduction in sodium intake can lower blood pressure by 8-10mm Hg. Sodium intake should be restricted to 1500-2300mg in those with hypertension. According to the Mayo Clinic, the DASH (Dietary Approaches to Stop Hypertension) diet can reduce blood pressure by up to 14mm Hg. The DASH diet is rich in whole grains, fruits, vegetables and low-fat dairy products and low in saturated fat and cholesterol.
• Alcohol. In small amounts alcohol can actually be beneficial for the cardiovascular system but the protective effect is lost if you drink too much. The NHS recommends that “men should not regularly drink more than three to four units a day and women should not regularly drink more than two to three units a day”. Check out this unit calculator if you’re wondering exactly how much a unit is.
• Smoking and second-hand smoke. Smoking can elevate your blood pressure by about 10mm Hg for up to an hour after smoking.
• Caffeine. Caffeine has been found to increase blood pressure temporarily but the long-term effects are still unknown. The Mayo Clinic recommend that you drink no more than 2 cups of coffee a day whereas the NHS recommend drinking no more than 4 cups a day. I guess it depends on the type of coffee you’re drinking!
• Stress. Stress and anxiety can temporarily increase blood pressure so relaaaaax! Yeah, I know, easier said than done…It helps if you can identify the cause and then take some steps to curtail or eliminate it. Breathing exercises, meditation, yoga, exercise, CBT, counselling, etc may help as well.

Remember to check your blood pressure regularly to see how well you’re doing and why not enrol family and friends to offer support and make sure that you stick to the programme!

BBC Horizon’s Truth About Exercise

Last month BBC Horizon ran a programme entitled “The Truth About Exercise”. In it Dr Michael Mosley travelled the country speaking to an assortment of Exercise Scientists. One of the first points made was that it takes a lot of exercise to burn calories. In fact, the example provided was that to burn off a cappuccino, a blueberry muffin and a banana, one would have to jog around a track for about 55 mins! Therefore, to stand any chance of losing weight, we must control what we eat.

Fortunately, exercise can have benefits even when no weight is lost. One of the benefits mentioned was the production of an enzyme that helps redistribute fat in the body and sends it to the muscles where it’s burned. This helps reduce the chance of getting atherosclerosis and possibly death from cardiovascular disease. Other health factors that can be improved are insulin sensitivity and the body’s maximum oxygen consumption (VO2 max). Insulin sensitivity is important because it means that blood glucose levels can decrease more rapidly thereby requiring less secretion of insulin by the pancreas. This reduces the likelihood of developing Type 2 diabetes. As for VO2 max, it’s been found to be a good marker of health and longevity.

Next, Dr Mosley met Jamie Timmons, professor of ageing biology at Birmingham University, and was told how training for 7 mins 3 times a week could deliver many of the health and fitness benefits of hours of conventional exercise! The training is called High Intensity Training (HIT) and resembles interval training. Interval training has been around for a long time and has been used by athletes to increase cardiovascular efficiency and increase tolerance to the build-up of lactic acid. The HIT protocol used on the programme was done on a static bike and consisted of: 2 mins warm-up, 20 secs full-out, 2 mins gentle, 20 secs full-out, 2 mins gentle and 20 secs full-out. This added up to a whopping 7 mins and was done 3 times a week for 4 weeks. It’s thought that this type of exercise can appeal to those that are time poor and need to get it done quickly or simply don’t enjoy it and so want to get it over and done with swiftly…hmmmmmm? It’s at this point that I became curious about exactly how many people fell into this category…so I did a little survey among some of my clients.

First I asked them whether they did any exercise or took part in any sports. Amazingly 95% of them did!

I then asked them how many times a week they exercised or took part in sports. Again I was surprised…an average of 3.6 times a week. I started wondering whether they were trying to please or impress me? Apparently 80% of the population doesn’t exercise regularly!

Finally, I asked them why they exercised? This was the last curveball…the most popular answer was because they enjoyed it…it made them feel good! Other popular reasons were for fitness, health (hypertension, diabetes, back pain) and weight loss.

So unfortunately there didn’t seem to be any takers for HIT. The claims are that HIT can give around 24% improvement in insulin sensitivity and 10% increase in VO2 max. After 4 weeks Dr Moseley did in fact improve his insulin sensitivity by exactly 24% but had no change in his VO2 max. His inability to improve his VO2 max was put down to genetics. According to Timmons, research has shown that 20% of the population doesn’t respond to endurance training.

What do I think about the HIT programme? Well, it paints exercising as a chore, but as the survey showed, most people get more from exercise or sports than just an improved insulin sensitivity…they enjoy it, it makes them feel good…possibly because of the endorphin release or a sense of achievement or accomplishment, maybe even because of social interactions? The HIT programme didn’t place much emphasis on fitness but other HIT protocols have. Gibala’s studies have shown benefits but his protocol was longer and a lot more gruelling…definetly not for everyone. There are many components to fitness: endurance, strength, flexibility, speed, agility, etc and I suppose people in the survey were happy to focus on particular aspects of this.

My main issue with the HIT protocol is its intensity. Pedalling “hell for leather” without a warm-up (not one that can be recognised as one anyway!) seems like a recipe for disaster. As a physiotherapist, I was a little uneasy watching Dr Moseley bounce around on his bike whilst pedalling as hard as he could for 20 secs…he should have known better after pulling a hamstring earlier in the programme when trying to sprint without any earlier warm-up…who knows, he may have felt comfortable doing it because he was surrounded by scientists? Surely this is not something that should be recommended to the sedentary masses?

The main drive of the HIT protocol seemed to be on health (primarily insulin sensitivity) and I think there are better, safer and more convenient ways of achieving this. New research published in the journal Diabetes Care has concluded that after meals, regular short bouts of light-intensity or moderate-intensity walking lower glucose and insulin levels. The subjects were asked to walk around for 2 mins every 20 mins. The light intensity walking decreased blood glucose and insulin levels by 24% compared to uninterrupted sitting. That figure is exactly the same as the one achieved by Dr Moseley after the HIT protocol.

If you enjoy exercise or sport and are happy with the fitness you’re achieving, keep it up! If you don’t enjoy exercise or sport and are mainly doing it for health or weight loss, you’re unlikely to keep going very long. My advice would be to focus on increasing your movement through activities of daily living…this was also talked about on Horizon but it seemed to get much less attention than HIT…in my opinion it’s where the real revolution lies…check in next week to find out more…

Can Exercise Really Lower Blood Pressure?

Blood pressure is the pressure exerted by the blood on the arteries and is measured in millimetres of mercury (mm Hg). There are two measures of blood pressure: the systolic blood pressure (SBP) is taken when the heart contracts and the diastolic blood pressure (DBP) is taken when the heart is relaxed. That’s why the systolic pressure is higher than the diastolic pressure. Blood pressure is considered high when it exceeds 140/90mm Hg and optimal blood pressure is 120/80mm Hg. High blood pressure or hypertension, as it’s also known, is a ‘silent killer’. ‘Silent’ because there are no signs unless it’s extremely high and ‘killer’ because it dramatically increases the risk of stroke, heart disease and kidney disease. Alarmingly, over 25% of adults in the UK have hypertension and that figure increases to more than 50% in those older than 60.

I was recently challenged by a client to provide evidence that exercise decreases high blood pressure. I think his exact words were…”where’s the evidence?” At first the question surprised me, but I soon realised he had a valid point. Why embark on a gruelling exercise programme without proof that it will actually fulfill the desired purpose?

So, here’s the evidence:

• Exercise decreases blood pressure in a staggering 75% of people with hypertension. On average, SBP decreases by 11mm Hg and DBP decreases by 8mm Hg. Now, if you’re thinking that those figures aren’t worth the effort…think again! The risks associated with hypertension are continuous. That means that with each 2mm Hg rise in SBP there’s an associated 7% increase in mortality from heart disease and 10% increase in mortality from stroke. So exercise alone can decrease your risks of dying from heart disease by just under 40% and decrease your risks of dying from stroke by 55%! Worth the effort?
• All guidelines (NHS, National Institute for Health and Clinical Excellence, American College of Sports Medicine, Canadian Hypertension Education Program, Mayo Clinic, etc) include exercise as a cornerstone in the prevention, treatment and management of hypertension.

Now that we know exercise works, here are some specific guidelines on how to go about it:

• Exercise should be undertaken on most days of the week and can include activities like gardening, household chores, walking, etc
• Perform primarily endurance exercise supplemented by some resistance work
• It should last 30mins a day (this can be continuous or accumulated over the day)
• The intensity should be 40-60% of reserve heart rate (low to moderate intensity exercise is as, if not more, beneficial as high intensity exercise)

What are you waiting for? Jump on that bike! Actually, before you jump on that bike, make sure you get permission from the owner and check with your GP as well. Next week, even more ways to help decrease blood pressure…

“The greatest test of courage on earth is to bear defeat without losing heart.”

Robert G. Ingersoll

Prolonged Sitting Affects Glucose Metabolism

New research published in the journal Diabetes Care has concluded that after meals, regular short bouts of light or moderate walking lower glucose and insulin levels. The subjects were asked to walk around for 2 mins every 20 mins. The effects of these short bouts of walking assist glucose metabolism and may reduce cardiovascular risk.

This adds to the mounting evidence regarding the health risks associated with prolonged sitting.

Metal On Metal Total Hip Replacements Unsafe?

A BBC Newsnight and British Medical Journal investigation has prompted a lot of discussion regarding metal on metal total hip replacements. Lately, a study has found that the metal components rub against each other causing small particles to break away into surrounding tissues. This leads to elevated blood levels of metal ions such as cobalt and chromium. The clinical significance of this is still unknown. The Medicines and Healthcare products Regulatory Agency (MHRA) have stated that annual blood tests should be conducted to check levels of cobalt and chromium. If levels are high, an MRI scan should be carried out to see if the prosthesis requires revision.

A recent technology overview conducted by the American Academy of Orthopaedic Surgeons (AAOS) has concluded that metal on metal implants are at greater risk of revision than replacements with different bearing surface combinations. This has come as a bit of a surprise as it was hoped that sturdy metal on metal implants would outlast metal on plastic implants. It was also noted that larger femoral head components are at higher risk than smaller ones and older patients also incur a greater likelihood of requiring another operation.

A previous technology review had found that hip resurfacing is more likely to need revising than total hip arthroplasties (THA). The size of the head is inversely related to the risk of revision. However, the Australian registry has suggested that younger men have less risk of revision with resurfacing than they do with THAs. This is interesting because research published in this month’s The Journal of Bone & Joint Surgery (British Volume) shows that the 10 year survival rate for a Birmingham hip resurfacing (BHR) is 89.1% for women and 97.5% for men. Mr AJ Shimmin et al. conclude that “BHR provides good functional outcome and durability for men, at a mean follow-up of ten years. We are now reluctant to undertake hip resurfacing in women with this implant”.

All this definitely provides food for thought and it’s well worth doing some research and having a long chat with your surgeon before deciding what sort of hip prosthesis to have.

Meditation Increases Blood Flow To The Brain

Recent research has shown that mantra-based meditation increases cerebral blood flow. An improvement in attention, emotional state and memory was also noted. Therefore, it’s likely that people with cognitive impairments or memory loss will benefit from meditation.