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Author: johnathan

The Efficacy and Importance of Pulse Oximetry – Acute Mountain Sickness

Predicting Acute Mountain Sickness using Pulse Oximetry Most trekking and expedition groups use pulse oximeters as a novelty item, and many groups carry a pocket pulse oximeter to periodically check the oxygen saturation (SpO2) as they as ascend the mountain. Pulse oximetry, though not 100% accurate, is useful in predicting acute mountain sickness (AMS). We all know that pulse oximeters are easy to use, noninvasive tools for the assessment of humans at high altitude. These instruments provide an estimate in percentage of arterial hemoglobin oxygen saturation, which is a function of arterial partial pressure of oxygen. The percentage denotes the hemoglobin binding sites that are occupied at any one time by oxygen. At sea level, healthy individuals will be on the “flat portion” of the oxyhemoglobin dissociation curve (see figure below), but at high altitude as the partial pressure of oxygen decreases with ascent, individuals will be at the “steep portion” of the curve (a slippery slope by comparison) where saturation changes significantly with respect to small changes in the partial pressure.   The higher the altitude, the higher the risk of symptoms like Acute Mountain Sickness (AMS) or High Altitude Pulmonary Edema (HAPE). Whether you are an athlete trying to increase your hemoglobin concentration or a mountain climber ascending Mount Everest, a pulse oximeter is important for several reasons while acclimatizing to altitude. Knowing that you are in...

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The Connected Athlete Podcast

The Connected Athlete / Barry Murray / Svein Tuft / Patreon Have you ever wanted to learn about how to optimize yourself in life and in sports? Irish Nutritionist, Barry Murray and Pro Tour cycling rider Svein Tuft can tell you how through years of training and coaching some of the world’s top athletes. Barry has legit nutrition degrees including a Bachelors and Masters in Science of Nutrition and Svein well known a veteran professional cyclist. Barry, a former chemist turned nutritionist has amassed a huge amount of knowledge on nutrition, health and performance. Barry is renowned for his expertise in endurance sports nutrition working with professional athletes such as Tour de France riders, World Class Triathletes, Gaelic Football County teams and Elite Distance Runners. Barry is passionate about speaking to all athletes interested in optimising their nutrition for endurance sports. He competes as an ultrarunner himself, last year winning The Wicklow Way 127km and The Kerry Way 200km ultramarathons. Svein Tuft, is a professional cyclist hailing from Canada, he rides for the Orica Green Edge team competing in races such as the Giro D’Italia and the Tour de France. Svein is also well known for his mountain treks in snow filled mountains surviving the elements and living off of the land. WHAT THEY DO Their approach to nutrition and lifestyle debunks the common myths around nutrition and challenges the accepted antiquated norm. The aim is to combine science, research and common sense to enhance performance and general health. Barry links science with practice and...

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Mel Pocock Story

Mel Pocock Story We all like stories about heroes and impossible situations. Here is an unlikely story about a European motocross racer name Mel Pocock. Mel hails from England and competes in the British and MXGP championships. Mel Pocock is a likable redhead by nature from East Sussex, England whose family has a strong tradition racing motocross. Mel had all of the attributes of a typical up-and-coming motocross racer growing up. He worked his way through the amateur ranks and achieving his professional racing license and getting picked up by a team. He experienced success along the way, placing...

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EV8 Video and Pics from Provence France

The EV8 velo route is progressing rapidly. Here are some pics and videos of the route between Sillans La Cascade and Flayosc. These videos are presented by Yves Manent of My Cycles in Carces, France. They rent all types of bicycles and electric bicycles. If you have any questions about the EV8, please don’t hesitate to email me at  I have a pretty good handle on the routes and some of the technicalities. Please check out the EV8 video ENJOY! Doc Edwards See the video of EV8 on the video below (click on the...

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The Efficacy and Importance of Pulse Oximetry – How sleep and training load can affect SpO2

How sleep and training load can affect SpO2 Athletes are very in tune with their bodies. Sometimes an athlete doesn’t wake up feeling right. Sometimes sleep is just not right. It is common to check heart rate and not much more. Have you ever thought about checking your blood oxygen (SpO2) with a pulse oximeter?   Case Report: The athlete woke up feeling just “not right” and he observed that his morning SpO2 was low on Tuesday after a big training block as seen with the Training Stress Score (TSS). The sleep hours were about 7 and 6 during this training block. The resulting SpO2 following the training block was 93%. This is a great case where the athlete may feel alright to go train and continue the hard exercises, but the fact of “not feeling right,” low sleep hours, and low SpO2 suggested that the athlete should either take the day off or train very light and concentrate on proper sleep. The athlete achieved 9 hours of quality sleep for 2 consecutive days and the SpO2 normalized and the following training days went very well.  This is a great example of how data is the “second voice” of the athlete and paying attention to the numbers can result in a good training block and even avoid an over-training scenario.   Johnathan Edwards is a medical doctor with 30...

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