Wednesday, 1 July 2015

Geeky Medics - Lower limb ulcers (arterial vs venous) article + quiz




I have written an article and created a quiz on lower limb ulcers which is now available over at Geeky Medics! 

To view the article - click here 
To go to the quiz - click here

They have lots of content to help medical students so definitely head over and give it a look. 

Friday, 11 January 2013

Are we are a society that accepts obesity?




When in any public place, whether that is in a shopping centre, park or walking down the road, seeing someone who is overweight or obese is not unusual anymore. Does this mean we have become a society that accepts an unhealthy appearance because we are so used to it? 60% of Australians are either overweight or obese which means that not only has our own quality of health decreased but our own self perception has lessened due to changes in western culture which can predominantly be put down to technology making our lives require less effort to live along side fast food to make it easier to eat and less effort to cook.

These combined factors are impacting on the health of both adults and children. Spotting a child at a shopping centre that has ankles so big because of adipose tissue (fat) surrounding them that he/she has feet that are splayed (pointing out) due to increased leg and stomach size. This is even more disturbing after seeing that child get up from a chair after eating McDonalds or KFC. Surely we cannot possibly accept this as a society? Where there is an obese child there is normally an obese parent who accompanies them which in my mind comes down to education and influence parents have over their children which is often underestimated or ignored completely.

Parents who have overweight children and are overweight themselves need to look in the mirror and ask themselves this. “Am I consciously slowly killing my child because of my habits and if this is the case where did I go wrong, why did this happen and what can I do to fix it before its too late and my child develops a serious medical condition?”  

Education is the main solution to this problem which is only going to get worse as technology gets more advanced and more fast food locations pop up around the place. Mobile phones, tablets and gaming consoles are stopping kids from going outside and exploring the world and doing physical activity. Parents who encourage this by buying these products are only adding to the problem. Takeaway food for dinner often is common practice now as its easier and fits around work. Home cooked meals are less common due to this which also takes away the ability of children to learn how to cook healthy meals. If they cannot cook healthy meals how will they teach their children and so on and so on? I am a firm believer in home cooked meals as you can choose what type of products you use i.e. organic vegetables and other organic products which can only help weight management and give you a greater understanding of portion control.

Education on physical activity, healthy eating and ways to reduce the use of technology can all lead to be a healthier and happier society. Parents need to take responsibility for their actions and start waking up to the serious implications of their actions. We need to question current habits instead of thinking its too hard to change or that there is no problem. If children under 15 are getting type 2 diabetes with an increased risk of cardiovascular disease then there clearly is a problem and its about time we saw this. If its normal for children to have a decreased live expectancy and for parents to outlive their children then this is a society that needs to question its beliefs, morals and attiudes towards life in general because we only get one and its currently being wasted.

Thursday, 10 January 2013

Is lactic acid related to muscle fatigue?

This report will examine the physiological parameters of what lactic acid is, if it is the main cause of muscle fatigue, how influences in pH levels change pH and how lactic acid affects patients with COPD (chronic obstructive pulmonary disease) when doing unsupported arm exercises in a controlled environment. The effect of lactic acid buffering in hyperventilation during exercise and how it relates to bicarbonate being readily accessible in the body during exercise will also be looked at to show its influence on muscle physiology.
  
Lactic acid forms in the body when different activities such as short sprints and spontaneous accelerated bursts of muscle contraction require the body to create more energy faster than its ability to deliver oxygen to the working muscles.
 
Because of this, the bodies tissues generate energy anaerobically through the process of breaking down glucose (a simple monosaccharide) into pyruvate (an organic acid and ketone). When there is enough oxygen in the body pyruvate is moved to an aerobic pathway for energy uses later on.
 
However when the oxygen concentration is limited in the body, pyruvate is converted into L-lactate from an enzyme called lactate dehydrogenase which allows glucose to be broken down and used as energy.  Muscle cells in the body can maintain production of anaerobic energy for one to three minutes. During this period lactate levels can increase.
 
This high level of lactate in the blood increases the acidity within the muscle cells which agitates other products of the bodies metabolism and reduces the capacity for high level function in exercise due to the acidic surroundings in the muscle cells, specifically the sarcomeres in which actin and myosin have play an important role in the function of (Roth, 2006 p 104) [10]. Lactate impedes production of acidosis however is not the cause of it (Kemp et al., 2006, p 235-237) [3]. Lactate is constantly generated by non-oxidative tissues meaning lactate needs to be resynthesized into the form of D-glucose in the liver at a flux rate of approximately 70g/day for an adult (Robinson, 2006, p 3-13) [9]. If levels fall below 70g the onset of hypoglycaemia is much greater (Hypoglycaemia, 2011) [7].   
 
What is the cause of muscle fatigue? Westerblad et al.,(2002, p 17-21) [12] states some recent studies conducted show that acidosis of muscle function has a minuet effect at physiological temperatures and that instead, inorganic phosphate which is present during fatigue due to creatine phosphate breakdown could be the major cause of muscle fatigue.
Having said this it does not mean acidosis has no effect at all. During strenuous exercise the intracellular pH of a muscle can decline by ~0.5 pH units. Studies have tried linking this pH decline to dysfunction of contractile ability to fatigue. Studies on muscle fatigue has shown a good relationship between reduced force production and muscle pH as well as a decline in ability to produce isometric force shortening velocity of the fibre as shown in Figure 1. 

Figure 1[13] - Readings from tetanic contractions of single fibre muscle from a mouse toe muscle. Solid line is controlled conditions. ~0.5 pH units was what fibre was acidified to. Acidification effect larger at 12⁰C than 32⁰C. Temperature raise decreases effect of acidosis on force production and maximum shortening velocity (Vmax).

Pate and colleagues research shows that acidification of a muscle fibre has a small effect on it’s shortening speed at 30⁰C.  A recent study also did not find a diminution of the metabolic processes glycolysis/glycogenolysis present in acidified muscle tissue (Pate et al., 1995) [4].
 
The total lactate produced daily via glycolytically is in the ranges of 70 and 110 g. 33.5 g comes from both the skin and red cells while an average of 20 g is from skeletal muscle and the brain and a very minuet amount from the intestinal muscosa. Removal rates tested after anaerobic exercise have been measured in the ranges of 250-330 g every 24 hours. This is extremely high and shows that homeotstatic function relies on synthesis rate by glycolytic tissues and the removal process. This is mainly by gluconeogenic tissues however the muscles oxidative removal process also contributes (Robinson, 2006, p 3-13) [9].
 
Westerblad et al.,( 2002, p 17-21) [12] also mentions that acidosis has little impact on isometric force production of a muscle fibre, rate of glycogen break down or maximum shortening velocity. If it does have a role to play in muscle fatigue then it has subsidiary effects. It is highly possible extracellular acidosis mobilises group III–IV nerve afferents in the muscle cell which could create a fatigue sensation in the body.  Elite athletes need to learn to cope with acidosis discomfort while optimally training their muscles which are not undeviatingly hindered by acidosis (Metabolic acidosis, 2011) [8].
 
Lactic acid can also have an impact on medical conditions. A study was conducted by de Souza and colleagues on 16 patients who had chronic obstructive pulmonary disease (COPD) to see if lactic acid levels increased when doing unsupported arm exercises doing diagonal movements using the proprioceptive neuromuscular facilitation technique (PNF) with a weight. During the study they assessed cardiovascular, ventilator and metabolic responses to the unsupported arm exercises. When the tests were conducted some physiological parameters were measured and recorded which were carbon dioxide production (VCO2), oxygen uptake (VO2), pulmonary ventilation (VE),  blood pressure (BP), heart rate (HR),  respiratory rate (RR) and blood lactate.
 
There was a pronounced increase in blood lactate levels along with VCO2, VO2, VE and RR from a resting position to the peak of the test.

Figure 2[2] - Blood lactate values in milimol per litre measured at rest, peak and 3 mins after the end of the unsupported arm exercise in chronic obstructive pulmonary disease (COPD) patients (median and range displayed).

Evidence found from the study does show that blood lactic levels increase in unsupported arm exercises in patients with COPD, with dyspnea (shortness of breath) a factor when unsupported as the respiratory and cardiovascular systems have to work harder however cannot work as effectively due to the physiological changes of COPD and because of this, acidosis on sets early in patients (de Souza et al., 2010, p 75-82) [1]. 
 
A study conducted by Péronnet and Aguilaniu looked at whether hyperventilation and the increase of VCO2 and VO2 above the ventilatory threshold (VTH) in exercise are directly the result of production of CO2 in the muscle in a nonmetabolic form because of lactic acid being buffered by plasma bicarbonate diffusing into the cell and exchanging with lactate.

Figure 3[6] – This shows the acid-base balance in muscle and the plasma CO2 being released from bicarbonate pool above VTH in reaction to exercise inclination.
(Wasserman, 1982, p 2039–2043)(10) Conducted research which states that standard plasma bicarbonate declines in a ~1:1 ratio when plasma lactate concentrations also increase with 1 mmol of CO2 being created above that with aerobic metabolism producing it for each mmol of lactic acid that’s buffered. Non metabolic CO2 produced in muscle cells is partly the cause of hyperventilation as CO2 has an increased flow to the lungs and limits the bodies ability to get rid of it.

Péronnet and Aguilaniu’s research shows this is not the case. A decrease in bicarbonate does not also represent an increase in lactate concentration nor is it the main buffer muscle uses. When bicarbonate is buffered it has no effect in creating increased CO2 levels in muscle.
The incommensurate surge in VCO2 at the mouth above the ventilatory threshold is evoked by hyperventilation and low plasma pH levels both lesson the bicarbonate ready to be used by the body. 
Bicarbonate is crucial in the pH buffering system the body has. If pH levels are too high or if the kidneys are not removing acid quickly enough from bodily fluids it is possible metabolic acidosis, specifically lactic acidosis, might onset of blood pH is <7.35. Hyperventilation impedes normal respiratory functions and can be a contributing factor as mentioned in the above research (Péronnet & Aguilaniu, 2006, p 4-18) [5].
Conclusion
 
This report has discussed what lactic acid is and the physiological processes involved in it’s occurrence and creation in the body when certain conditions cause acidosis. Furthermore the likelihood of it being the sole cause of muscle fatigue is unlikely with creatine phosphate breakdown being the plausible answer however that does not mean lactic acid plays no part in it’s prominence in fatigue physiology. It also plays a role in the pathophysiology of COPD and hyperventilation during exercise. In COPD when performing unsupported arm exercises with weight there is an increase in blood lactate levels during and after exercise and onsets earlier with ventilator output being one of the limiting factors in patients with COPD. In hyperventilation low plasma pH is part of the cause of the body having limited access to bicarbonate during exercise.
 
In muscle fatigue, COPD and hyperventilation, lactic acid may not always be the independent cause of pathophysiological changes in the body however it does not act alone which should be considered when analysing blood lactate during fatigue in exercise and examining medicals conditions that involve respiratory and cardiovascular changes in conjunction with muscle physiology to get a clearer understanding as to how each process and system functions together to create a physiological change in homeostasis.



Reference list:
1. de Souza et al., (2010). Lactic acid levels in patients with chronic obstructive pulmonary disease accomplishing unsupported arm exercises. Sage Journals, 7, 75-82. doi: 10.1177/1479972310361833 [1]

2. de Souza et al., (2010). Lactic acid levels in patients with chronic obstructive pulmonary disease accomplishing unsupported arm exercises [Image]. Retrieved September 14, 2012, from http://crd.sagepub.com.ezp01.library.qut.edu.au/content/7/2/75.full.pdf+html [2]

3. Kemp, G., Böning, D., Beneke, R., & Maassen, N.(2009). Explaining pH Change in Exercising Muscle: Lactic acid, Proton Consumption, and Buffering vs. Strong Ion Difference, 29, 235-237. doi: 10.1152/ajpregu.00662.2005 [3]

4. Pate et al., (2003). Reduced effect of pH on skinned rabbit psoas muscle mechanics at high temperatures: implications for fatigue. The Journal of Physiology, 486, 689-694. Retrieved from http://jp.physoc.org/content/486/Pt_3/689.abstract?ijkey=be508d743692cce0f8bd171710429f7042203879&keytype2=tf_ipsecsha[4]

5. Péronnet, F., & Aguilaniu, B. (2006). Lactic acid buffering, nonmetabolic CO2 and exercise hyperventilation: A critical reappraisal. ScienceDirect, 150(1), 4-18. Retrieved from http://www.sciencedirect.com.ezp01.library.qut.edu.au/science/article/pii/S156990480500100X [5]

6. Péronnet, F., & Aguilaniu, B. (2006). Lactic acid buffering, nonmetabolic CO2 and exercise hyperventilation: A critical reappraisal [Image]. Retrieved September 14, 2012, from http://www.sciencedirect.com.ezp01.library.qut.edu.au/science/article/pii/S156990480500100X [6]

7. PubMed Health: Hypoglycemia (2011). Hypoglycemia. Retrieved from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001423/ [7]

8. PubMed Health: Metabolic acidosis (2011). Metabolic acidosis. Retrieved from http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001376/ [8]

9. Robinson, H. B. (2006). Lactic acidemia and mitochondrial disease. ScienceDirect, 89(1-2), 3-13. Retrieved from http://www.sciencedirect.com.ezp01.library.qut.edu.au/science/article/pii/S1096719206001958 [9]

10. Roth, M, S. (2006). Why does lactic acid build up in muscles? Scientific American, 294, 104. doi: 10.1021/jf900623w0406-104 [10]

11. Wasserman, K., (1982). Dyspnea on exertion. Is it the heart or the lungs? JAMA 248, 2039–2043]. Retrieved from http://jama.jamanetwork.com/article.aspx?articleid=379021 [11]

12. Westerblad et al., (2002). Muscle Fatigue: Lactic Acid or Inorganic Phosphate the Major Cause? American Physiological Society, 17(1), 17-21. Retrieved from http://physiologyonline.physiology.org/content/17/1/17.long#ref-14 [12]

13. Westerblad et al., (2002). Muscle Fatigue: Lactic Acid or Inorganic Phosphate the Major Cause? [Image]. Retrieved September 14, 2012, from http://physiologyonline.physiology.org/content/17/1/17.long [13]
 

Friday, 7 September 2012

Exercise and Hypothyroidism



Hypothyroidism is a medical condition in which the thyroid gland, which is located just below the voice box, does not make enough thyroid hormone in the body. The thyroid has the job of deciding how quickly the body uses energy and it's sensitivity to other hormones. Some of the hormones it produces play a role in the metabolic rate and influences other systems in the body.

Hypothyroidism is not to be confused with Hyperthyroidism, as hyper means that the thyroid gland is overactive and exercise should be avoided unless cleared and supervised by a medical professional.

In terms of exercise, aerobic activities and strength training can be the most beneficial for someone who has this condition. By doing aerobic exercise it will also reduce the risk of cardiovascular diseases such as coronary artery disease and metabolic disorders like type 2 diabetes.

If you do have Hypothyroidism it is important to get clearance from a medical professional before undertaking any exercise program.

References:

Betty Holt. (2011). What Is the Best Workout If You Have Hypothyroidism? . Available: http://www.livestrong.com/article/477000-what-is-the-best-workout-if-you-have-hypothyroidism/. Last accessed 7th September 2012.

Saturday, 7 April 2012

Glut tightness and myofascial pain



Buttock pain is quite common and can be caused by a number of things, such as repetitive gluteus muscle work without stretching, a tight piriformis muscle contributing to glut pain and pelvic instability/incorrect posture.

There are three different gluteus muscles which are gluteus maximus (biggest), gluteus medius (medium sized) and gluteus minimus which is the smallest out of the three. Gluteus maximus is important in hip extension when walking and running and as such, can become tight if used repetitively for activities such as sprinting and jumping. Both gluteus maximus and medius can become tight and cause pain due to the role they play at the hip joint. Gluteus medius, and to a small extent minimus, have the role of hip stability and control when walking and running.

So what is myofascial pain exactly? To put it simply, it is when "knots" appear in the muscle which cause muscle tightness and lead to pain. This can lead to pain in the gluteus muscles and can possibly travel down the back of the leg if the piriformis muscle is also involved and leading to impingement of the sciatic nerve. This can be a sign that there is tightness present, along with possible reduced hip movement due to the pain and tightness itself.

There a number of ways to diagnose myofascial pain. MRI, CT scans and muscle ultrasounds can all diagnose it however, a good doctor or physio should be able to pick it up without the need for further scans unless other problems may be present and a more detailed look is needed.

If you do have tightness in that area there are a few ways to relieve some pain. The most common is following a stretching program given to you by a physio which will aim at increasing your flexibility in that area which will help undo some of the muscle knots and improve your posture.

There are some self ways to relieve some of the tension, which are self trigger pointing. Trigger points are area's in the muscle which have increased blood supply due to things such as poor posture or repetitive movements that lead to tightness and myofasical pain. By applying pressure to a trigger point, it takes blood away from that area and allows the muscle to relax.

Tennis balls and golf balls can do the trick however there are proper trigger point products on the market. The diagram above is a trigger point spot which you can apply pressure to on the buttock and where the pain might be felt.

If you are unsure you should always consult a physio before trying self trigger points.




Saturday, 10 March 2012

Cycling, ITB syndrome and knee stability



ITB syndrome, also known as ilio tibial band syndrome, is a medical condition where the ITB, which attaches from the tensor fascia latae and is a broad band of fascia, becomes inflamed due to repetitive movements that cause it to rub over the lateral femoral epicondyle (bony part on outside of knee). The movements that most commonly lead to this are excessive hip flexion/extension movements, which are always used in cycling which makes it one of the main causes of this condition.

Other activities that can bring about ITB syndrome are soccer, deadlifts and squats, rowing and running.

Even though ITB has the role of supporting the knee in extension, when it becomes tight it can pull your patella (knee cap) laterally, which isn't good for knee stability and medial tracking of the patella during movement. On a side note, people who have genu valgus (knocked knees) and pronate when they walk/run are more likely to have a tight ITB as well.

Vastus medialis, the inside quadriceps muscle and specifically the obique fibres, have the role of helping maintain knee stability and the muscle also does medial tracking of the patella. If the ITB is tight it's going to pull the patella laterally which doesn't allow the VMO muscle to be used, which leads to weakness and more chance of injury.

Some of the forms of treatment are stretching, corrective exercise, ice and rest. Personally, stretching and corrective exercise go hand in hand so I will list some basic exercises that can help stretch the ITB to relieve inflammation and to improve knee joint stability through muscle activation exercises.

1. ITB stretch - There are a number of ways to do this and this is just one of them. If you have time, 2-3 times a day would be ideal. Click here to view. (Stretch #15). 


2. ITB roll - Personally, I think a foam roller is much more effective than a stretch, as it applies more pressure on the area and allows it to be stretched more which leads to the collagen fibres tension being reduced. Click here to view. (Exercise #10).


3. VMO (Vastus medicalis obliquus activation) - This is a simple exercise you can do that will help activate the VMO muscle. I have an explanation on how to do it under the picture. Click here to view. (Exercise #9). 


if you are a cyclist who is suffering from this condition, give the above exercises a go. Even if you don't cycle and you know you have a tight ITB, they can also work for you! If you are unsure if you have it then consult a doctor or a physio for more detail information relating specifically to your symptoms.

Sunday, 26 February 2012

Basic weight loss and health tips


I have decided to make a list of some basic tips that can not only help lose weight, but also keep your body healthy through good habits and reduce the risk of other problems like heart disease.

  • Exercise for at least 30 minutes a day at a moderate intensity 5 days a week, daily if possible. Cardiovascular fitness can help reduce the risk of heart disease and high blood pressure through weight loss. It can also improve symptoms of type 2 diabetes.
  • Have 6 meals a day and eat a small snack in between your main meals every 2-3 hours to keep your metabolism regulated.
  • Have at least 2 servings of fruit and 5 servings of vegetables a day. Nutrients from both of these can improve your health and bodily functions. A serving is 1 cup.
  • Eat oily fish at least twice a week to get your omega 3 intake which can help maintain cardiovascular function.
  • Park your car further away from work or the train station so you can walk or use the stairs instead of an escalator or lift. 
  • Drink between 2-3L of water a day to help look after your kidneys.
  • Get between 7 and 9 hours of sleep a night.
  • Eat plenty of cereals, breads, noodles and rice for energy. Low GI foods are going to give you energy that lasts a longer period of time. Complex carbohydrates are what we need every day in order to function.