Boot camp Melbourne

Cholesterol is a type of fat found readily in the cells of the human body, a waxy type substance that is vital for key metabolic processes, including hormone production and the body’s ability to utilise vitamin D.  However, for all its important functions high levels of cholesterol can be severely detrimental to our health, in particular the increased risk of coronary heart disease and atherosclerosis (narrowing of arterial walls.)    

HDL & LDL, the good & the bad

In order to better understand cholesterol and its effect on our health we must first realise that cholesterol is generally separated into two different categories.  Low density lipoprotein (LDL) cholesterol and high density lipoprotein (HDL) cholesterol.  You may already know about these types of protein, better known as ‘bad’ cholesterol (LDL) and ‘good’ cholesterol (HDL.)  Lipoproteins are simply transporters, they carry cholesterol from the liver out into the blood stream.  LDL are the major carriers of cholesterol from the liver to the rest of the body, which is a necessary function.  The problem arrises when the levels of cholesterol in the body are excessive and LDL deposit cholesterol along arterial walls causing damage.  On the other hand we have HDL, the function of which is to clear the blood stream of excess cholesterol and deliver it back to the liver thereby reducing the risk of it lining arterial walls.

Getting the right ratio

So now that we understand cholesterol in its various guises the sixty-four million dollar question is how can I develop a healthy ratio of LDL and HDL for the optimum function of the body?  Like most quandaries of health and fitness the answer is a balance of a healthy eating plan and regular exercise.  Now whilst this article focuses on exercise and its effect on cholesterol let me make a couple of points in regards to food and the role it plays on cholesterol levels.  Cholesterol is produced by the body inside the liver and a healthy adult is more than capable of synthesising the majority of the bodies needs.  Cholesterol also comes into the body through food, known as ‘dietary’ cholesterol.  It is through this supply that we often consume far more cholesterol than is required.  Staying clear of saturated and trans fats and replacing them with polyunsaturated and mono-unsaturated oils is the perfect starting point to help redress the bodies natural balance. 

Effects of exercise

Regular participation in physical activity as well as a single exercise session can positively alter cholesterol metabolism (Durstine & Haskell, 1994). However as the term exercise is rather broad we need to define what type of exercise is required to positively alter cholesterol levels. More specifically aerobic exercise (walking, jogging, swimming, bike riding etc.) has been shown to be the most effective in positively altering HDL cholesterol levels (Kokkinos & Fernhall, 1999). Although a large body of research has been conducted into the area of exercise and cholesterol only very broad conclusions can be drawn from the results.  However, for both men and women it has been shown that exercise volume rather than exercise intensity is the more important factor. Elevated HDL levels have been reported in women following a high-volume training program (Williams 1996, Williams 1998) but not for those in a low-volume training program (Brownell et al. 1982). So what does that mean for those of us looking to modify our cholesterol levels? The key is to participate in continuous aerobic activities, using major muscle groups in an attempt to elevate heart rate for a sustained period of time. The optimal training frequency is approximately 3 to 5 times per week (ACSM 1998), however if capable it appears that the more frequent the better, ideally six days a week with the obligatory rest day.  In other words the more often you can walk the dog round the block, jump on the treadmill or hit the tennis court with friends the better. 

Get started today

Start by greeting the early morning sun with a 30min walk in your local neighbourhood three to four days a week. Over a period of eight to ten weeks you should look to progress that to 45-60min worth of aerobic exercise five to six days per week. You should attempt to keep your exercise at a moderate intensity level, using a scale of zero to ten, with ten being maximum effort and zero being sedentary you should aim for a personal effort level of sex to seven. So as your fitness levels increase over time you will need to increase the intensity of your exercise to keep at the same personal effort level, changing your walk from flat to hilly ground or breaking into a jog are easy ways to modify your routine.

It is clear that exercise plays an important role in maintaining optimum cholesterol levels and along with a healthy eating plan should be mainstays of overall health and vitality.  Once again the answers to a question of health and fitness come down to a simple concept, look after your body and it will look after you.

Joshua Humphrey
Lecturer – Australian Fitness Academy
www.fitnesseducation.com.au

American College of Sports Medicine. 1998. ACSM’s Resource Manual for Guidelines for Exercise Testing and Prescription, Third edition. Baltimore: Lippincott Williams and Wilkins.
Brownell K.D., P.S. Bachorik & R.S. Ayerle. 1982. “Changes in plasma lipid and lipoprotein levels in men and women after a program of moderate exercise”. Circulation. 65(3):477-84.
Durstine J.L. & W.L. Haskell. 1994. “Effects of exercise training on plasma lipids and lipoproteins”. Exercise and Sports Science Reviews. 22:477-522.
Kokkinos P.F. & B. Fernhall. 1999. “Physical activity and high density lipoprotein cholesterol levels”. Sports Medicine. 28(5):307-14.
Williams P.T. 1996. “High-density lipoprotein cholesterol and other risk factors for coronary heart disease in female runners”.334(20):1298-303.
Williams P.T. 1998. “Relationships of heart disease risk factors to exercise quantity and intensity”. Archives of Internal Medicine. 158(3):237-45.