Timing of nutrient intake

 

Pre-exercise

The prominent macronutrient that needs to be
utilized in the days and hours before training/competition is carbohydrates. At
9am, client 2110 ate oats with semi skimmed milk, followed by a yogurt, which
equated to 40.3g of carbohydrates. A few hours later at 11am the client had
noodles followed by a cereal bar which contained 35.3g of carbohydrates. Therefore,
in total, the athlete consumed 75.6g of carbohydrates before competition (2pm).

Carbohydrate oxidation, gained from muscle glycogen utilization, specifically during
the first hour of prolonged exercise, has been seen to increase with the
ingestion of a rich carbohydrate meal 4 hours prior to exercise (Coyle et al.,
1985). Similarly, Hargreaves et al. (2004) suggests that a 200-400g
carbohydrate meal 2-4 hours before exercise, combined with an overnight fast
the night before, can restore endogenous reserves of carbohydrates and is
coupled with improved performance. This research insinuates that client 2110
may not be consuming enough carbohydrates prior to exercise, in turn, not
providing adequate glycogen stores to fuel energy during training/competition. On
the other hand, carbohydrate intakes of 1-4g/kg/BW, within 1-4 hours in advance
of exercise, have been revealed to enhance endurance or performance during
prolonged exercise (Thomas et al., 2016). The athlete had consumed 1.16g/kg/BW
of carbohydrates 3 hours before exercise began therefore suggesting that the
client had a sufficient amount of carbohydrates and glycogen stores. Athletes
that train and compete at high intensities for prolonged periods of time could
benefit from carbohydrate loading 1 day prior to competition. Athletes were
asked to perform 150s of hard exercise split into 120s of cycling at 130% VO2max,
instantly followed by 30s “all out” effort. The participants then consumed a
rich carbohydrate diet (10-12g/kg/BW), mainly from high glycaemic index foods,
consequentially after 24 hours muscle glycogen stores were extremely high
(averaging 180mmol/kg w.w.) (Fairchild et al., 2002).

 

The aim of pre-hydration is to achieve a state of
euhydration. This can be done 2-4 hours before exercise by consuming between
5-10mL/kg/BW. In doing so, the athlete should achieve a urine colour of pale
yellow and give adequate time for excess fluid to be excreted prior to exercise
(Thomas et al., 2016). Further research from Sawka et al. (2007), suggests that
the individual should slowly drink ~5-7mL/kg/BW at least 4 hours before
exercise begins. At 9am the client drank 500ml of water, followed by a further
1000ml at 11am. Therefore, the client’s total fluid intake was 1500ml (~23mL/kg/BW)
and would have been well hydrated before competition but is significantly higher
than the research advocates. This could possibly mean that the athlete was hyper
hydrated, which can potentially dilute and lower plasma sodium (Sawka et al.,
2007). To inhibit this, Murray (1987) recommends a 200ml drink which contains
50mmol/L of sodium between a 3-10% concentration will increase fluid absorption
in the small intestine.  

 

During exercise

Dehydration of 1-2% of body weight onsets the
compromise of physiologic function and negatively influences performance,
therefore athletes should maintain hydration at less than 2% body weight loss (Casa
et al., 2000). In this case, the client should aim to stay above 63.7kg to
prevent a >2% body weight fluid reduction. This is emphasised as Edwards et
al. (2007) found that when fluid ingestion was prohibited to football players,
the total distance covered was reduced by 13-15% compared to individuals who
could ingest fluid, demonstrating the detrimental physiological effects lack of
hydration has on athletes.

 

Covertino et al. (1996) suggest that during
exercise, athletes should try to drink fluids at regular intervals in an
attempt to ingest fluids at the same rate as they are losing water (body
weight) through sweating. These fluids should be readily available for the
athletes to allow prescribed amounts of fluid to be drank with minimal interruption.

For general guidance, the fluid guidelines that are most appropriate for the
majority of athletes are between 0.4-0.8L/h, whilst consuming beverages
containing electrolytes and carbohydrates can provide greater benefits than
plain water (Sawka et al., 2007). Client 2110 managed to consume just 500ml of
water throughout the game, suggesting that they did not drink enough fluid
according to this research.

 

For prolonged exercise greater than 1 hour, it is
recommended that 20-40mmol/L of sodium is to be included in fluids that are
consumed during exercise, by minimizing hyponatraemia. Hyponatraemia is caused
by drinking low-sodium containing solutions (Coyle, 2004). In addition to sodium,
carbohydrates can also be added to fluids taken during exercise, or in other forms
such as bars and gels. It is recommended that during intense exercise lasing
>1 hour, carbohydrates should be ingested at a rate of 30-60g/h to delay the
onset of fatigue whilst maintaining carbohydrate oxidation (Sawka et al., 2007).

This research is supplemented further as endurance athletes are advised to
ingest carbohydrates at a rate of 60g/h. Additionally, small amounts of carbohydrate
ingestion during exercise has the ability to improve performance of athletes
that compete in intermittent team sports (>75% VO2max) due to the
mechanism of the central nervous system, activating reward centres (Cermak and
Van Loon, 2013). As client 2110 did not consume any form of carbohydrates
during exercise, the athlete should practise a refuel plan that suits hydration
needs as well as minimising gut discomfort (Thomas et al., 2016).

 

Post-exercise

One of the goals concerned with post-exercise recovery
is restoring depleted glycogen levels, whilst maximising the efficiency of
refuelling time. It is suggested that within the first 4-6 hours, athletes are
to consume ~1-1.2g/kg/h of carbohydrates (Thomas et al., 2016). Conversely,
there are many factors that affect recovery and ultimately can prohibit the
athlete in consuming recommended foods and fluids, such as loss of appetite and
having no access to satisfactory foods. During the early recovery phase, there
has seen to be some advantages of meeting carbohydrate goals through a series
of snacks, however during longer recovery time periods (24h) the athlete should
arrange the order and timing of rich carbohydrate meals in accordance with what
is most comfortable and pragmatic (Burke et al., 2004). Client 2110 consumed a
meal 45 minutes after exercise had finished. This meal contained 2 slices of Hovis
bread (38.1g carbohydrates, 9.6g protein) and turkey slices (2.4g of
carbohydrates, 46g of protein).

 

During the first few hours of recovery, it is recommended
that the ingestion of a meal/snack containing ~20g of protein has shown to
stimulate protein synthesis whilst inhibiting protein breakdown (Beelen et al.,
2010). However, this does not work effectively without good daily timing of
protein. Areta et al. (2013) concluded that 4x20g protein every 3 hours was the
superior feeding pattern method to stimulate muscle protein synthesis, compared
with 8x10g and 2x40g. Hours later, at 7:30pm, the athlete consumed beef burgers
containing 63g of protein, in bread rolls (14.1g protein), with beans (7.2g
protein). As stated previously, beef is a good example of a high-quality source
of protein, providing the athlete with essential amino acids to build and
repair damaged tissues.

 

Post-exercise, the objective is to fully replace
any fluid and electrolyte lost. If the athlete is significantly dehydrated,
coupled with a short recovery period until their next competition/training
session (<12 hours), an aggressive rehydration plan should be considered (Sawka et al., 2007). As client 2110 has a gym session the following morning, this suggests that they should have a rehydration program in place. Shirreffs and Maughan (1998) concluded that fluid ingestion should be a volume equal to 150% of their mass lost, therefore the client should drink approximately 1.5L of fluid for each kilogram (1L) lost. The athlete consumed 500ml of water 45 minutes after exercise, followed by another 500ml of plain water with their evening meal. The inclusion of dietary sodium, both from fluids and/or food, helps to retain ingested fluids, specifically extracellular fluids such as plasma volume (Thomas et al., 2016). As sodium is the superior electrolyte of both extracellular fluid and sweat, drinks ingested should contain enough sodium to replace that lost in sweat during the dehydration process (Shirreffs et al., 1996).