Paul Bateson from Team Axarsport has been good enough to send us the results of a scientific study that some runners in last years Al Andalus Ultra Trail event took part in. For those that don’t know, The AAUT is the premier Spanish multi-stage trail event, attracting leading ultra runners accross the world. Last years winner was Lahcen Ahansal, multi-time Marathon Des Sables winner. The AAUT is notoriously tough with temperatures equal to and even exceeding some popular desert race. A team from Coventry University followed a sample of last year’s competitors thorugh their pre-race preperation and monitored them throughout the event.
If you are taking part in a desert hot-climate ultra, then these results will prove interesting reading.
Assessment of Nutritional & Hydration Habits of Ultra-Marathon Runners During a Semi Self-Sufficient Ultra-Marathon Competition in a Desert Based Environment:
2010 Al Andalus Ultra-trail (219km) 12-16th July 2010
Coventry University Applied Research Group: Overall Research Results
Feedback Team: Abigail Swancott, Lisa Hardy, Dr. Andrew Murray, Dr. Ricardo Costa.
Note: The following set of results reflects the overall average of the race outcomes. Dietary guidance and recommendations given only reflect a general approach to improving nutrition and hydration for ultra-marathon competition in a hot ambient environment.
Results presented are overall average from all stages.
Limited number of runners performed carbo-loading prior to the ultra.
Limited number of runners heat acclimatised prior to ultra.
- Increasing total carbohydrate intake (food or fluid) while reducing training load at least three days prior to competition has been shown to substantially increase muscle glycogen
- (carbohydrate stores in the muscle) content which will be used during competition, and promote a good starting base from a multi-stage race.
- Performing a heat acclimation protocol (e.g. Costa et al., 2010; see attachment; x2 2h medium intensity runs during the week prior to ultra-competition in the heat (>30C) will assist the body to adapt to running in the heat; thus, improving hydration status, thermoregulation and reduce cardiovascular strain during competition.
- Heat acclimation was evident (increases/retentions in body water- classical sign of heat
adaptations) in majority of runners during the first two days of competition only.
Main take home message: It is important to carbo-load and acclimatise to the race environment prior to multi-stage competition.
Estimated energy expenditure lower limit: 3986Kcal
Estimated energy expenditure upper limit: 4786Kcal
Energy intake: 3324Kcal
Pre-ultra to post-ultra weight difference: 0.5kg weight loss.
- A small weight loss was observed between pre-ultra and post-ultra weight in the majority of runners. This may be indicative of the small negative energy balance observed.
- There were no differences in body fat or body lean tissue induced by the ultra, and hydration levels were maintained during the ultra in the majority of runner. Therefore, the small weight loss may possibly be due to daily fluctuations in muscle glycogen (muscle carbohydrate) level since sub-optimal daily carbohydrate intake was observed in the majority of runners.
Main take home message: Increase carbohydrate energy to meet exercising energy demands.
1. Overall dietary intake
- Carbohydrate intake: 529g/day; 8.0g/kgbw/day; 64% of energy intake.
- Protein intake: 105g/day; 1.6g/kgbw/day; 12% of energy intake.
- Fat intake: 88g/day; 1.3g/kgbw/day; 23% of energy intake.
- Proportion of macronutrient intake for exercise optimal (64% carbohydrate; 12% protein, 24% fat).
- Adequate protein intake for exercising needs in majority of runners.
- Suboptimal carbohydrate intake for exercising on consecutive day in majority of runners.
- Carbohydrates predominantly from sugars sources, such as carbohydrate rich drinks (e.g. soda, fruit juice, isotonic drinks, recovery drinks), energy bars, cereal bars, gels, and sweets.
- Fat profile needs adjusting in majority of runners: 26g/day saturated fat; 24g/day
- monounsaturated fat; 37g/day polyunsaturated fat (poor omega 3 intake); 1g/day Trans-fatty acids.
- Reasonable fibre intake (18g/day) predominantly from fruit and cereal bars.
Main take home message: Maintain protein intake; Increase carbohydrate rich foods within meals, snacks and carbohydrate rich fluids; Modify fat profile by focusing on predominantly monounsaturated based fats.
2. Intake pre-stage (awakening until stage start):
Protein: 22g (13%)
Carbohydrate: 102g (62%)
Fat: 19g (24%)
- Macronutrient energy distribution in accordance with exercising needs.
- Carbohydrate intake reasonable in majority of runners.
- Fat intake may be slightly high prior to exercise onset.
Main take home message: Increase carbohydrate rich foods and possibly decrease fatty food for the breakfast prior to the stage onset. This can be easily achieved by increasing the portion of carbohydrate rich breakfast foods or by including a carbohydrate rich drink with breakfast. Adding carbohydrate to drinks will also help with fluid replenishment.
3. Intake during-stage:
Carbohydrate: 23g/hr of competition
- Carbohydrate intake during exercise sub-optimal in all runners.
Main take home message: Try to develop strategies during training (food or fluid based strategies) that will cater for at least 30g/hr of carbohydrate, with an overall aim of achieving intakes of ~60g/hr.
4. Intake post-stage (<1hr post-stage):
Protein: 15g; 0.2g/kgbw
Carbohydrate: 118g; 1.8g/kgbw
- Carbohydrate intake optimal for recovery in majority of runners.
- Protein intake suboptimal for recovery in majority of runners.
Main take home message: Try to develop strategies (food or fluid based strategies) that will cater for at least 1.2g/kgbw of carbohydrate and 0.4g/kgbw of protein immediately after exercise (e.g. fortified milk shake or recovery drink).
- Total daily fluid intake: 8134ml/day= of which carbohydrate rich fluids: 2422ml/day + of which plain water: 5712ml/day.
- Fluid intake pre-stage (awakening until stage start): 856ml total= of which carbohydrate rich fluids: 233ml total + of which plain water: 623ml total.
- Fluid intake during-stage: 730ml/hr of competition= of which carbohydrate rich fluids: 200ml/hr of competition + of which plain water: 530ml/hr of competition.
- Fluid intake post-stage (<1hr post-stage): 1270ml total= of which carbohydrate rich fluids: 729ml total + of which plain water: 541ml total.
Main take home message: Ingestion of plain water should be avoided. Fluids consumed should contain some carbohydrate (e.g. 4-8%; 4-8g/100ml of fluid) and electrolytes (especially sodium and potassium).
Body weight loss pre to post-stage: 1.9kg = 2.7%
Urine specific gravity (hydrated: <1.020g/ml): pre= 1.031, post= 1.046
Urine Osmolality (hydrated normal range: <600mOsmol/kg): pre= 662, post= 896
Urine colour (hydrated normal range: <3): pre= 4, post= 6
Bodystat total body water (hydrated normal range: 41-48L): pre= 44, post= 46
Bodystat Extracellular water (hydrate normal range: ~19L): pre= 19, post= 19
Bodystat Intracellular water (hydrate normal range: ~25L): pre= 24, post= 26
- Fluid losses during exercise: 908ml/hr of competition (includes sweat and urine losses).
- In accordance with Bodystat BIA analysis- current total daily fluid intake + fluid intakes pre, during, and post-stage are sufficient to maintain hydration in the majority of runners.
- The average 2.7% (1.9kg) body weight loss observed post-stage appears not to be related to loss in total body water through sweat; therefore are likely to reflect exercise induces losses in muscle glycogen (carbohydrate stores in the muscle) levels, and possibly water losses through urine.
- Using urine measures of hydration during multi-stage ultra-marathon competition in the heat may be inappropriate and give an inaccurate measure of hydration status. This is primarily due to heat acclimatisation adaptation (e.g. the body will try to prevent inappropriate water losses. Therefore, constantly produce concentrated urine no matter what the body’s hydration status).
- 98% of runners reported urinating at least once during stages. This is an indirect indicator of excess water intake being above sweat losses.
Main take home message: Current fluid ingesting (see fluid intake results) is sufficient to maintain hydration during multi-stage ultra-marathon competition in the heat. However,
focus should be on always including carbohydrates and increasing electrolyte concentration (especially sodium- e.g. a pinch of salt) of all fluids ingested, and avoiding the consumption of just plain water.
(note: sodium is the main extra-cellular electrolyte; while potassium is the main intra-cellular electrolyte. Both have important roles in maintaining hydration. However, sodium is the predominant nutrient involved in controlling water flow within the body, and it is also the main electrolyte which is significantly lost through sweat. Therefore, sodium needs replacing more frequently than other electrolytes. Other electrolyte (magnesium, calcium, phosphate, bicarbonate and chloride) are also important in hydration, however their turnover (storage, utilisation and losses) is slow and more long-term. Therefore, meeting daily dietary needs can easily meet the demands of these electrolytes even during periods of strenuous exercise in hot ambient environments (For more information refer to the literature provided in the eference list).
- Overall dietary intake: Adequate electrolyte intake (sodium intake= 3633mg/day; 466ml/L
- fluid; salt equivalent= 9.1g/day; 1.1g/L fluid).
- Pre-stage (awakening until stage start): Adequate electrolyte intake (sodium intake= 1180ml/L fluid; salt equivalent= 2.9g/L fluid).
- During stage: Suboptimal electrolyte intake (especially sodium & potassium; sodium intake=219ml/L fluid; salt equivalent= 0.5g/L fluid)
- Post-stage: Suboptimal electrolyte intake (especially sodium & potassium; sodium intake=
- 371ml/L fluid; salt equivalent= 0.6g/L fluid)
Main take home message: Increase electrolyte intake during and after exercise. Practical recommendations include: a) add a pinch of salt to all fluids consumed (e.g. a pinch of salt to a 500ml or 750ml water bottle; add two pinches to a 1000ml water bottle); b) use an electrolyte mixture and add an additional pinch of salt (all electrolyte mixtures contain relatively low amounts of sodium per portion used). Electrolyte mixtures do not contain sufficient sodium to replenish heat exercise sweat losses- they mainly focus on replacing all/selective electrolytes (e.g. disease based dehydration- losses of all electrolytes). During exercise in the heat a substantial amount of sodium is lost compared with other electrolytes.
General vitamin & mineral intake:
Vitamins: over UK recommended nutrient intake (RNI)
Minerals: over UK recommended nutrient intake (RNI).
Main take home message: Maintain intake of a variety of foods from different food groups.
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Feedback comment posted by Adwin Gallant:
I participated in this study in 2011 and looking very much forward to see the research results.