Aerobic Detraining

Whether it is injury, sickness, travel, planned training cessation or insufficient amount of training –reversibility of previous gained performance improvement, Detraining, can happen. The decrease in performance will affect you depending on your current status and the time of your interruption (short term, 3-4 weeks and long term >4 weeks). Bear in mind, that as I discuss the physiological effects of short term aerobic detraining, the word detraining will be used to describe a period without training, compared to tapering which sometimes mistakenly is used interchangeably.  

Cardiovascular effects of aerobic detraining. An increase in blood volume, mainly plasma volume (already after first session), is one of the first endurance adaptations. However, it also decreases to pretraining level within one week (~ -12% decrease for 2.91l -2.56l plasma). In an attempt to maintain cardiac output (Q, circulation) for muscular blood supply, your heart will pump faster (~ 4% increase in HR) to make up for decreased stroke volume (SV, amount of blood pumped out with each beat) and decreased ventricular size.  

Since Q is affected, VO₂max will drop proportional to quantity and therefor have a greater effect on highly trained individuals than moderately trained, example ~8% eg. 62.2-57.3ml/kg/min.

For all Exercise Physiologists...

VO2 max=Q x (a-vO2max)

It’s been shown that VO₂max remains 3% lower even after reestablished SV, indicating importance of other metabolic factors. However, one should keep in mind that recent data has shown that VO₂max might not be the best predictor of performance among high level athletes.

At the Muscular level of aerobic detraining capillary density is reduced, but not enough to return to pretrained state within four weeks of detraining. This will could possibly be another factor affect SV. Additionally, it reduces the gas exchange necessary for aerobic metabolism which in conjunction with reduction of oxidative enzymes leads to an increased reliance on anaerobic metabolism. This shift towards anaerobic reliance has been shown through an increase in RER, respiratory exchange ratio, at set intensity. RER is the difference between carbon dioxide produced and oxygen used, measure in exhaled air as carbon dioxide is a byproduct of anaerobic metabolism. 

RER=(Volume CO2)/(Volume O2)

Another supported factor for an increased glycogen dependency is related to the decrease in muscle GLUT-4 transporter protein. GLUT-4 is responsible for transport glucose (carbohydrates) into the sarcoplasm for glycolysis (glucose breakdown for anaerobic ATP production) or glycogen synthesis (glucose storage). It might sound contradicting that lack of this transporter would increase use of carbohydrates. However, GLUT-4 is stimulated by the combination of insulin and exercise.  Since lack of exercise decreases insulin sensitivity, leaving a lot of glucose in rested state, the uptake will be increased during exercise. Increased insulin sensitivity with training will enable GLUT-4 activity and glucose uptake even in rested state. Therefore, some research states that GLUT-4 activity decreases only as a secondary outcome of decreased insulin sensitivity. Additionally, the fat enzyme muscle lipase has shown to decrease during inactivity meanwhile increasing at the adipose tissue leaving less room for breakdown and more for build up of fat.

It is possible that short-term detraining have a greater effect on peak aerobic performance as submaximal performance has shown to be maintained amongst distance runners while endurance trained athletes decreased their TTE (time to exhaustion) with 4-25%. The increased lactate production might be one of the factors. As lactate is a product of glycolysis, this increased dependency on glucose will increase blood lactate with a greater change in trained individuals.

While muscular glycogen has shown to decrease with as much as 20% in one week, other anaerobic substrate has not been studied as much in short term detraining and/or not shown to a change indicating that it needs longer time for detraining and would relate more to detraining in relation to resistance training. The same is true for hormonal changes.

So does this mean that days and periods off are bad? Absolutely not. The importance of recovery days and off season is well knows. However, it’s importance to differentiate between detraining, off season and other light periods following an athletes periodization. 

This article is based on content and sources in the review by:

Review by:
Mujika, I., Padilla, S., Detraining: Loss of Training-Induced Physiological and Performance adaptations. Part I. Sports Med, 30 (3): 145-154, 2000.

Additional sources

McArdle, William D., et al. Exercise Physiology: Nutrition, Energy, and Human Performance. 7th ed., Wolters Kluwer Health/Lippincott Williams & Wilkins, 2015.

Searching the secret in Failing

I don't want to say that Failure always is something positive, likewise it is not always negative. Failure only defines you if it makes you stop, if not, you learned something from it that should assist you going forward. The old saying strength is defined by how many times your rise from the fall..hand in hand with that, stupidity can defined by how many times you rise after falling over the same hurdle.

Ask yourself "what will I do different this time?" 

Use your knowledge?
Be honest to yourself

Create a plan

Follow and trust the process
See your results

that's what I'm going to do, feel free to sit back and follow the show.

Sofia

Nutritional timing, Part IV: Should I eat breakfast if I want to loose weight?

In previous blog entry, I briefly mentioned data suggesting the relationship between a higher total caloric intake throughout the day and the majority of energy consumed in the evening[1]. This has been one of the main argument supporting the importance of eating breakfast in the morning. Kids, adolescence and adults are commonly told by personal trainers, exercise physiologists, parents and even Siri that “breakfast is the most important meal of the day”. Is that true?

The importance of breakfast is related to factors associated with over-night fast. As a result of not eating for an extended period of time, the energy stored in our blood and muscles will be lower. This will result in an increased use of fat compared to carbohydrates as energy. While this might sound great for individuals desiring to lose fat, one needs to understand that the body still requires a certain amount of energy derived from carbohydrates to function properly which instead of being provided through food, will be taken from stores in the body such as the muscles. 

Recent data suggests that consuming breakfast will result in decrease risk of weight gain and better maintenance of weight balance due to increase satiety, lower desire to eat and perceived hunger throughout the early and/or late morning periods. This results in an overall lower caloric consumption  throughout the day which ease maintenance of energy balance. The national weight control registry reported that among the population who has a successful weight loss maintenance, 78% consumed breakfast[2].

Consuming breakfast has shown to affect the hormonal levels and brain activity in our body that are associated with stimulation of appetite and feelings of satiety. Ghrelin has been defined as the hormone that stimulates appetite and was decreased following breakfast, and brain activation pattern signaling energy intake have showed to change following a meal[3] [4]. This lower desire to eat and greater satiety are directly related to amount of snacking. Breakfast-skippers consume more food through snacking compared to breakfast consumers. In addition to greater frequency, their go to snack tend to be unhealthy and consist of foods high in calories [5]. Meanwhile, consumption of a breakfast showed to decrease the urge for frequent unhealthy snacking, enabling the breakfast eaters to replace cravings for unhealthy snacks usually consumed in the evening, with nutritious food consumed in the morning [3].

Further, it has been suggested that breakfast composition (amount of fat, protein and carbohydrates) might play a role for additional benefits of breakfast consumption. Recent data has shown that consuming a breakfast high in protein (31g) prevents fat gain an promotes weight balance through decrease in hunger and lower caloric intake not only in the morning, but throughout the entire day compared to skipping breakfast, consuming a low protein breakfast (13 grams of protein) and consuming the protein in either lunch or dinner other meals[6]. Higher protein content in the breakfast might decrease total amount of calories consumed late in the evening, 656 ± 108 kcal compared to 486 ± 84 kcal as well as calories consumed as carbs and fat.

While these are great news for breakfast lovers, there are a big population who struggle with food intake in the morning, but don’t worry. First of, consuming breakfast does not mean that you have to go straight from your bed and into the kitchen. The benefits of eating breakfast has been shown when the window of no food consumption in the morning is four hours which will give you some leeway in the time to wake up before consuming breakfast. Secondly, 350 calories which was the standard breakfast used in a lot of the studies is not a lot of food. In order to get 31 grams of protein and 350 calories, all you would have to eat is 1 cup of yogurt, 1 banana and 1 egg.  

[1] Castro JM. The time of day and the proportions of macronutrients eaten are related to total daily food intake. Brit J Nutr 98, 1077-1083, 2007.

[2] Wyatt HR, Grunwald GK, Mosca CL, Klem ML, Wing RR, and Hill JO. Long-term weight loss and breakfast in subjects in the National Weight Control Registry. Obes Res 10:78–82, 2002.

[3] Leidy HJ, Ortinau LC, Douglas SM, and Hoertel HA. Beneficial effects of higher-protein breakfast on the appetitive, hormonal, and neural signals controlling energy intake regulation in overweight/obese, “breakfast-skipping”, late-adolescent girls. Am J Clin Nut 97: 677-688, 2013.

[4] Van Vugt DA. Brain imaging studies of appetite in the context of obesity and the menstrual cycle. Hum Reprod Update 16:276–92, 2010.

[5] Deshmukh-Taskar PR, Nicklas TA, O’Neil CE, Keast DR, Radcliffe JD, and Cho S. The relationship of breakfast skipping and type of breakfast consumption with nutrient intake and weight status in children and adolescents: the National Health and Nutrition Examination Survey 1999-2006. J Am Diet Assoc 110: 869–78, 2010.

[6] Leidy HJ1, Bossingham MJ, Mattes RD. Campbell WW Increased dietary protein consumed at breakfast leads to an initial and sustained feeling of fullness during energy restriction compared to other meal times. Br J Nutr 101:798-803, 2009.

Nutritional timining, Part III: Should I eat before going to sleep if I want to loose weight?

 Should I eat in the before going to sleep if I want to lose weight?

Late night cravings and hunger, everyone has it once in a while and most people dislikes it since good eating habits carried out through the entire day easily can be ruined by excessive late night snacking. Eating just before going to sleep can have detrimental effects on your weight loss plan, especially considering the kinds of food that we tend to eat just before bedtime, high in fats and carbs and foremost high in calories which when consumed excessively is the primary reason for weight gain.

The general understanding among people is that eating late at night is bad since your metabolism is slower during night time and extra food consumption during this time will be stored as fat. This is somewhat true. The energy expenditure has been showed to decreases with as much as 35% already during the first half of 8 hours of sleep and remain lowered, with the decrease in fat oxidation being the main contributor for the decline in metabolism[1]. This decrease in fat metabolism has been suggested to last for as long as 24 hours if consuming a nigh time snack about 200 calories consisting of a protein: fat: carbohydrate ratio of 5:50:45 at 11 pm every day for two weeks[2], while consumption of late night snack on a single occasion showed no effect on fat metabolism[3]. Additionally, research has shown a correlation between energy intake in the evening and total daily energy intake where the population consuming majority of their food in form of fat, carbohydrates or total amount of calories in the evening reported lower satiety and more calories consumed throughout the day [4]. This results in a greater total calorie consumption and increased risk for weight gain.

However, recent studies suggests that eating in the evening might not necessarily be bad if you control for total amount of calories consumed. By making sure to eat smaller, nutrient-dense meals instead of large mixed meals the night time snack could potentially be beneficial. Eating a small meal consisting of ~150 calories, 30-40 grams of either carbohydrates or protein around 30 minutes before going to bed can actually increase morning metabolism and satiety in both active [5] and sedentary obese individuals[6].

Energy requirements varies depending on multiple different variables, one is related to “the thermogenic effect of food”. This is the energy required to digest the food that one consumes. There are a lot of data indicating that proteins (both whey and casein) have greater thermogenic effect compared to carbohydrates [7] (ARCIERO). This is due to the fact that protein takes longer for the body to break down and digest compared to carbohydrates. This means that protein, especially in the slow digested form of casein, consumption causes a greater increase in metabolism and energy requirement and has therefore been suggested as preferred macronutrient for late night snacking. However, some studies comparing the results following consumption of carbohydrates, whey protein or casein protein 30 minutes before bedtime showed similar improvements in insulin and morning metabolism and satiety (KINSEY).

So to summarize it: most research that associates late night snacking with negative consequences have used fatty snacks high in total amount of calories. Replacing these kind of foods for proteins and carbohydrate (about 40g, 150-200 calories) will ensure guilt free late night snacking that potentially can help you in the weight loss process due to increase night time metabolism.

  Example of foods that would be good as night time snack are presented in the table below.

	Fat	Carbs	Protein	Calories
1 cup 0% Fage Plain Greek yoghurt with ½ cup raspberries	0	17	24	166
½ cup low fat cottage cheese with 1/3 cup of low sugar granola	5	19	16	181
Special K Chocolate Peanut Butter Protein bar	6	25	10	170
Muscle Milk, ready to drink, protein shake	8	8	16	160
¼ cup Hummus with 1 cup Carrot sticks	6.3	21	6	156

 

 

 

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[1] Katayose Y, Tasaki M, Ogata H, et al. Metabolic rate and fuel utilization during sleep assessed by whole-body indirect calorimetry. Metabolism 58, 920–926, 2009.

[2] Hibi M, Masumoto A, Naito Y, et al. Nighttime snacking reduces whole body fat oxidation and increases LDL cholesterol in healthy young women. Am J Physiol Regul Integr Comp Physiol 304, 94–101, 2012.

[3] Whitehead JM, McNeill G & Smith JS. The effect of protein intake on 24-h energy expenditure during energy restriction. Int J Obes Relat Metab Disord 20, 727–732,1996.

[4] Castro JM. The time of day and the proportions of macronutrients eaten are related to total daily food intake. Brit J Nutr 98, 1077-1083, 2007.

[5] Madzima TA, Panton LB, Fretti SK, Kinsey AW, Ormsbee MJ. Night-time consumption of protein or carbohydrate results in increased morning resting energy expenditure in active college-aged men. Brit J Nutr 111: 71-77, 2014.

[6] Kinsey AW, Eddy WR, Madzima TA, Panton LB, Arciero PJ, Kim JS, and Ormsbee MJ.Influence of night-time protein and carbohydrate intake on appetitie and cardiometabolic risk in sedentary overweight and obese women. Brit J Nutr 1-8, 2014.

[7] Arciero PJ, Ormsbee MJ, Gentile CL, Nindl BC, Brestoff JR, and Ruby M. Increased protein intake and meal frequency reduces abdominal fat during energy balance and energy deficit. Brit J Nutr 21, 1357–1366, 2013.

Nutritional Timing, Part II Training in a fasted State Resistance Training

Nutritional Timing, Part II Training in a fasted state: Resistance Training

Should I eat before lifting?

First of, what did we establish in last entry about fast and endurance training that potentially can be applied towards resistance training?

1. Low carbohydrate availability forces the body to increases the usage of Fat as a fuel.
2. Chronic performance improvements (power, oxygen uptake, and time to exhaustion) has been seen when training in fasted state from both high and low intensity training.
3. Performance can be maintained if total amount of calories needed is consumed.
4. Fueling the body before training could result in a lower amount of fat usage during the session, but increase the calories used throughout the entire day.
5. Waking up at 5am or working out hungry is no fun.

Generally, the physical activity associated with weight loss is cardio. However, resistance training [1] and other high intensity training methods[2]  has shown to increase the rate of fat usage immediately after the training session and can therefore assist in both decreasing fat mass and increasing fat free mass. Additionally, the more muscle a person have relative to total body mass, the higher the amount of energy needed will be.

Okay, but back to the question, what will happen if you don’t eat before your weight lifting session? The main reason for weight training is muscle growth. Muscle growth is dictated by the overall balance of protein (muscle) synthesis[3] and protein degeneration making up for muscle protein balance. Training stimulates synthesis and degeneration at the same time.  Whether you have a positive or negative muscle balance during your work out is largely determined by the food that you eat before your session. Amino acids are parts of protein that serves as building blocks in our muscles. If one has a greater amount of these building blocks circulating around in the body going in to training, it will be easier for the muscle to pick them up[4]. If fasting, you will have a negative muscle balance during your training session since there are no building blocks for the muscles to take up. Additionally, hormone availability are important for muscle synthesis⁵. Since nutrition has shown to elevate hormonal levels during training, fasting result in decrease amount of hormones responsible for muscle synthesis.

Carbohydrates are stored in the muscles as glycogen and are used as the main fuel during resistance exercise[5]. The general belief is that if you don’t refill these stores, training will result in muscle breakdown which is the natural catabolic effect of fasting. Even if there are a lot of support behind this theory, some of it is subjective rather than objective [6]and performance have been shown to be maintained even when training fasted.

The difference in the chronic results seen in regards to fasted versus fed and resistance training responses could potentially be related to something referred to as anabolic super compensation[7]. Which means that the anabolic response might be stimulated and elevated when fasting, resulting in an even greater muscle synthesis post resistance training to make up for the lowered synthesis response during the training bout³. This is supported by studies not showing a different in results when food was ingested at different times but the total energy intake was matched for[8] [9]

Finally, the importance of a pre-work out meal is highly related to the type of exercise performed. Figure one ⁵ serves as a good guideline to whether you should eat before your work out or not. However, it doesn’t seem like there is a direct and significant benefit of performing resistance training fasted. So even if data shows that your body will be able to super compensate for what was lost during the session in a fasted state, spare yourself the potential demotivation and feelings of fatigue such as lack of energy and eat before your session rather than relying on your post-work out meal to satisfy your needs.

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[1] Ormsbee M. J, Thyfault P. J, Johnson A. E, Kraus M. R, Choi D. M, Hickner C. R. Fat metabolism and acute resistance exercise in trained men. J Appl Physiol 102(5), 2006.

[2] Warren A, Howden E J, Williams A D, Fell, J W, Johnson A N. Post exercise fat Oxidation: Effect of exercise Duration, Intensity, and Modality. Int J Sports Nutr Ex Metab 19: 607-623, 2009

[3] Kumar V, Atherton P, Smith K, Rennie J. M. Human muscle protein synthesis and breakdown during and after exercise. J Appl Physiol 106:2026-2039, 2009)

[4] Tipton K. D, Rasmussen B. B, Miller S. L, Wolf S. E, Owens-Stovall S. K, Petrini B. E, Wolfe R. R. Timing of amino acid-carbohydrate ingestion alters anabolic response of muscle to resistance exercise. Am J Physiol Endoctrinol Metab 281: 197-206, 2001.

[5] Helms R E, Aragon A A, Fitschen J P. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation.  J Int Soc Sports Nutr 11: 1-20, 2014.

[6] Zerguini Y, Kirkendall D, Junge A, Dvorak J. Impact of Ramadan on physical performance in professional soccer players. Br J Sports Med 41:398–400, 2007.

[7] Deldicque L, De Bock K, Maris M, Ramaekers M, Nielens H, Francaux M, Hespel P. Increased p70s6k phosphorylation during intake of a protein-carbohydrate drink following resistance exercise in fasted state. Eur J Appl Physiol 108:791-800, 2010.

[8] Trabelsi K, Stannard R S, Ghlissi Z, Maughan J R, Kallel C, Jamoussi, Zeghal M K, Hakim A. Effect of fed- versus fasted state resistance training during Ramadan on body composition and selected metabolic parameters in bodybuilders. J Int Soc Sports Nutr 10: 1-11, 2013.

[9] Tipton D. K, Tabatha A. E, Cree G. A, Aarsland A.A, Sanford P. A, Wolfe R. R. Stimulation of net muscle protein synthesis by whey protein ingestion before and after exercise. Am J Physiol Endocrinol Metab 8:71-76, 2007.