January 2021 – Running

Drink to thirst

20th January 2021 Quintus Van Rensburg No Comments Health, Supplements

Hyponatremia is a condition of low sodium concentration in the blood. Prolonged overhydration during exercise is the primary cause of all forms of exercise-associated hyponatremia (EAH) and should be avoided. The updated EAH clinical practice guidelines issued by the Wilderness Medical Society stress that individuals engaged in physical and endurance activities should drink to satisfy their thirst (known as “drink to thirst”) to avoid overhydration. The guidelines appear in Wilderness & Environmental Medicine, published by Elsevier.

Review articles and international consensus statements have mainly focused on the incidence of EAH in organized endurance events that are conducted in the frontcountry, where medical tents and local emergency medical services are typically available on site and transport to a local hospital is readily available. However, many prolonged individual exertional activities such as backpacking, ultramarathons, and multiple-day endurance events take place in the backcountry with limited or no medical support and expectations of delayed medical evacuation.

Appropriated management of EAH depends first on correctly diagnosing the condition. The guidelines address the assessment of patients with overlapping or nonspecific signs that can make differential diagnosis challenging, for example, with heat exhaustion or exertional heat stroke.

The guidelines recommend that:

Appropriate education and coordination among participants, event directors, support crews, park rangers, first responders, and EMS transport personnel are essential in both prevention and management of EAH.
Prolonged overhydration during exercise, which is the primary risk factor in the development of all forms of EAH, should be avoided.
Sodium and/or salty snacks should be freely available for consumption along with the appropriate fluids, particularly in long, hot events in non-heat acclimatized persons.
Participants should drink enough to satisfy their thirst but avoid overdrinking.
Point-of-care testing should be done on at-risk, symptomatic patients, when available.
Oral fluids should be restricted if EAH from fluid overload is associated with mild symptoms.
Hypotonic fluids are contraindicated with suspected EAH.
The use of oral salt or hypertonic fluids may be effective in reversing moderate to severe symptoms of EAH when no IV hypertonic saline (3 percent) is available.
Patients should be observed for at least 60 minutes after exercise to ensure no decompensation from delayed symptomatic EAH.
Receiving caregivers should be alerted to the potential diagnosis of EAH and fluid management restrictions when transferring care.

EAH is generally defined as a sodium concentration of less than 135 mmol/L (135 mEq/L), with severe EAH being below 120 mEq/L. Symptoms may include nausea and vomiting, headache, short-term memory loss, confusion, and lethargy, altered mental status, coma, seizures, and/or respiratory distress, some of which can be confused with other medical conditions.

Heel-toe or toe-heel?

14th January 2021 Quintus Van Rensburg No Comments Biomechanics, Running technique

New research from La Trobe University suggests there is no evidence that changing a runner’s strike pattern will help prevent injuries or give them a speed boost.

In a bid to avoid shin splints, sore knees and other injuries, many runners have adopted a toe-to-heel trend, running on the balls of their feet. This is often encouraged by coaches and health professionals.

However, in research out this week in Sports Medicine, La Trobe injury researcher and physiotherapist Dr Christian Barton found there is no evidence to suggest running on the front of your feet reduces injury risk or improves performance.

The comprehensive review suggests that telling someone to run on the ball of their foot instead of their heel may make them less efficient, at least in the short term. Additionally, there is no evidence either way on whether running on the balls of your feet reduces injury.

Dr Barton said switching your running style shifts the body’s loads but doesn’t make them disappear.

Running toe-heel might help injuries at the knee, where loads are reduced. However, it may cause injuries to the feet and ankle, where loads are increased.

Put simply, when it comes to running style: If it ain’t broke, don’t fix it.

Morning or Evening

8th January 2021 Quintus Van Rensburg No Comments Training

Researchers from the University of Copenhagen have learned that the effect of exercise may differ depending on the time of day it is performed.

We probably all know how important a healthy circadian rhythm is. Too little sleep can have severe health consequences. But researchers are still making new discoveries confirming that the body’s circadian clock affects our health.

Researchers from the University of Copenhagen – in collaboration with researchers from the University of California, Irvine – have learned that the effect of exercise may differ depending on the time of day it is performed.

There appear to be rather significant differences between the effect of exercise performed in the morning and evening, and these differences are probably controlled by the body’s circadian clock. Morning exercise initiates gene programs in the muscle cells, making them more effective and better capable of metabolising sugar and fat. Evening exercise, on the other hand, increases whole-body energy expenditure for an extended period of time.

The researchers have measured a number of effects in the muscle cells, including the transcriptional response and effects on the metabolites. The results show that responses are far stronger in both areas following exercise in the morning and that this is likely to be controlled by a central mechanism involving the protein HIF1-alfa, which directly regulates the body’s circadian clock.

Morning exercise appears to increase the ability of muscle cells to metabolise sugar and fat, and this type of effect interests the researchers in relation to people with severe overweight and type 2 diabetes.

On the other hand, the results also show that exercise in the evening increases energy expenditure in the hours after exercise. Therefore, the researchers cannot necessarily conclude that exercise in the morning is better than exercise in the evening.