Exercise as it relates to Disease/Intensity of exercise in men for optimal fat oxidation

What is the background to this research

What is the article about

The article being critiqued is a study conducted on a male population to assess the effects of fat oxidation during different intensities of exercise. Using indirect calorimetry and exercise bikes the study attempts to shows that the effects of fat oxidation in exercise increase from low intensity to moderate intensity and decrease from moderate to high intensities (1). Different control groups within the study were also assessed on dietary factors that contribute to fat oxidation during exercise. These groups involve high carbohydrate consumption and overnight fasts which showed a greater increase in fat oxidation during fasted state but this is considered debatable by the researchers. This study may be flawed as it only assessed 25 fit individuals but showed that fat oxidation was fairly inconstant across different intensities. These studies still followed the initial assumption of moderate intensity being the best for fat oxidation.

How is this article important

This is an important article for health related aspects as it may contribute to knowledge in burning fat and decreasing obesity. Obesity is known to cause negative health effects such as cardiovascular disease which increases sick leave and may even have a negative effect on the workplace (2). The negative health effects of obesity include increased chances of cardiovascular disease, diabetes, musculoskeletal disorders and more (3). These negative health effects lead to a decrease in longevity of individuals and put further strain on the economy as a whole. Studies show that obesity has caused a loss of 1.3 billion in the American state of New Mexico (4). The economic effects of obesity further contribute to the importance of the article being critiqued as it may help to decrease the economic burden of obesity.

Where is the research from

Background to the author

The article being critiqued was constructed by A. E. Jeukendrup which is short for Asker Jeukendrup (1). Jeukendrup is a sports nutritionist, participates in ironman competition and has a PhD on the effects of fat and carbohydrate metabolism during exercise. As a sports nutritionist Jeukendrup is well educated in the field of health and exercise and is well equipped to suggest interventions and write articles that can help prevent diseases caused by sedentary behaviour and a lack of physical fitness.

Background to the institution

The article written by Jeukendrup was written through the University of Birmingham in England. This institution is considered one of the top four universities in the UK in the sports and exercise science field. Up until 1968 sports were compulsory at this university which showed it understands the need for exercise better than many institutions across the globe.

What kind of research was this

What type of study is this

The article being critiqued is a cohort study as it places groups of people in differing conditions and assesses their progress. Research suggests that cohort and case control studies are the best when it comes to assessing risks associated to any particular population (5).

Could it be better

A case control study may have worked just as efficiently as it would have assessed the results of fat oxidation over a long period of various exercise intensities. Any other study such as randomized controlled trials and systematic reviews may not have replicated the same results as most data suggests moderate intensity is substantially better. This is not the case for the article being critiqued as it suggests only a slight increase in fat oxidation at moderate intensity.

What did the research involve

Participants in the article

There was said to be 25 participants in the article being critiqued with an already existing knowledge in the fitness levels required to burn fat. These participants each are said to have normal amounts of body fat or low amounts of body fat. Studies show that lower weight individuals burn less energy and as a result have a lower rate in fat oxidation (6).

What other people could have been involved

As weight gain will affect energy expenditure it may have been appropriate for overweight individuals to be added to the cohort study to gain a more positive effect on fat oxidation at various exercise intensities across the general population. Further studies show that women have greater fat storage and lower fat oxidation rates than men (7). Including a female group in the cohort study of the article being critiqued will have offered further variation.

Were references appropriate

Each reference used in the article being critiqued are very accurate to the purpose of which they were being used.

What were the basic results

Outcome of article

The outcome of the article being critiqued seems to be a success as far as replicating the pre-assumed results. Moderate intensity exercise shows the greatest increase in fat oxidation although it is not a substantial increase from low intensity. The rate of fat oxidation decreases significantly once high intensity exercise begins to take place (1). This means that for the purpose of losing weight for health related reasons an individual should engage in moderate intensity exercise to achieve a better result.

Are they as accurate as others

Other tests such as “The effects of increasing exercise intensity on muscle fuel utilisation in humans” published by The Journal of Physiology are good for assessing fat oxidation (8). This article focuses too much on all types of energy metabolism while the article being critiqued focuses on only fat oxidation making it far more unique. All other articles seem to prove that moderate intensity is the greater intensity for fat oxidation. This shows that the article being critiqued is accurate to other peer reviewed research.

What conclusions can we take from this research

Review on the study

The study seems to have been a major success with each participant showing results that prove the assumption to be correct. Although particular groups could be added to the article it was not completely necessary in proving that moderate intensity exercise increases fat oxidation.

Critique myself

My own critique, although well researched, may be lacking as I myself am not a PhD graduate. This critique was done as a type of meta-analysis where I picked out other peer reviewed research articles to prove studies conducted within the article being critiqued.

Practical advice

What could he do better

One of the flaws seen in the article being critiqued is the limit on testing used to assess fat oxidation. It is known that ketone bodies will increase in urine samples during fat oxidation and could have been another way to assess fat oxidation. A study conducted on obese people showed an increase in the production of ketones during a period of fasting (9). A urine strip can be used very easily to assess the level of ketone in a urine sample.

Further information/resources

If further information is required by an individual seeking to learn as much as possible about fat oxidation, there is a list of 25 references used in the article being critiqued. These can add to the knowledge someone can obtain from this article.

References

• 1. Achten J, Jeukendrup AE. Maximal fat oxidation during exercise in trained men. International journal of sports medicine. 2003 Nov;24(08):603-8.
• 2. Robroek SJ, van den Berg TI, Plat JF, Burdorf A. The role of obesity and lifestyle behaviours in a productive workforce. Occupational and environmental medicine. 2011 Feb 1;68
• 3. Van Itallie TB. Obesity: Adverse effects on health and longevity. American Journal of Clinical Nutrition. 1979.
• 4. Frezza EE, Wachtel MS, Ewing BT. The impact of morbid obesity on the state economy: an initial evaluation. Surgery for Obesity and Related Diseases. 2006 Sep 1;2(5):504-8.
• 5. Meirik O. Cohort and case-control studies. Geneva: World Health Organization. 2008.
• 6. Weyer C, Pratley RE, Salbe AD, Bogardus C, Ravussin E, Tataranni PA. Energy expenditure, fat oxidation, and body weight regulation: a study of metabolic adaptation to long-term weight change. The Journal of Clinical Endocrinology & Metabolism. 2000 Mar 1;85(3):1087-94.
• 7. Blaak E. Gender differences in fat metabolism. Current Opinion in Clinical Nutrition & Metabolic Care. 2001 Nov 1;4(6):499-502.
• 8. van Loon LJ, Greenhaff PL, Constantin‐Teodosiu D, Saris WH, Wagenmakers AJ. The effects of increasing exercise intensity on muscle fuel utilisation in humans. The Journal of physiology. 2001 Oct;536(1):295-304.
• 9. Reichard GA, Owen OE, Haff AC, Paul P, Bortz WM. Ketone-body production and oxidation in fasting obese humans. The Journal of clinical investigation. 1974 Feb 1;53(2):508-15.