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!

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…

“Every patient carries her or his own doctor inside”.

Albert Schweitzer

“To ensure good health: eat lightly, breathe deeply, live moderately, cultivate cheerfulness, and maintain an interest in life.”

William Londen

Tai Chi Improves Balance In People With Parkinson’s

Parkinson’s disease is a degenerative disorder that affects dopamine-generating cells in the central nervous system. The physical symptoms are the classic triad: shaking, rigidity and slowness of movement. Posture, walking and balance are also impaired. Dr Fuzhong Li and colleagues studied the effects of Tai Chi on patient’s with Parkinson’s. Amongst other benefits, they found that Tai Chi improved posture, walking ability and decreased the number of falls.

Previous research has already found that Tai Chi reduces falls among the elderly. In fact it’s slow, fluid movements over a firm, balanced stance seem like an ideal form of exercise for aging populations.

Exercise Promotes Cellular Housecleaning

Aging, infections and diseases such as cancer, neurodegenerative disorders, inflammatory diseases and insulin resistance can all be caused by a buildup of waste products and debris within cells. It’s by a process called autophagy, an intracellular recycling system, that cells maintain their ideal environment. A group of researchers have found that exercise helps boost autophagy.

For a more in-depth analysis of the research, have a look at “Exercise as Housecleaning for the Body” in The New York Times.

“In health there are neither rewards nor punishments,

There are only consequences”.

Robert G Ingersoll

Exercises As Effective As Manipulation For Neck Pain

A recent study has found that spinal manipulation therapy is more effective than medication in both the short and long-term. The most interesting part of the study was that home exercises and advice were as effective as manipulation. It just goes to show that the benefits of self-help should not be underestimated. It would have been interesting to compare a combination of spinal manipulation therapy and home exercises…which in my opinion would have yielded the best results.

More Proof That Exercise Improves Health

A team of researchers have identified a new hormone named irisin. It’s produced by exercise and increases the metabolism and the sensitivity to blood sugar levels. This in turn may make us less susceptible to obesity and diabetes.

Yet more proof that exercise is beneficial…if we needed any more!