Erhalten Sie Zugang zu diesem und mehr als 300000 Büchern ab EUR 5,99 monatlich.
- Herausgeber: Books on Demand
- Kategorie: Ratgeber
- Sprache: Englisch
Regular and prolonged swimming in the sea, in addition to the pleasure it provides, has beneficial effects on health, but it can also present certain risks. This book explores the physiological effects of swimming, particularly in cold water ( 10 to 14 °C), in the light of recent data. The author presents a complete picture of the benefits and risks of this activity. He offers advice and recommendations for safe swimming in the sea in all seasons. This book is intended for those who are interested in this activity and want to start in the best conditions, but also for experienced swimmers who want to go further in the understanding of their practice.
Sie lesen das E-Book in den Legimi-Apps auf:
Seitenzahl: 142
Veröffentlichungsjahr: 2023
Das E-Book (TTS) können Sie hören im Abo „Legimi Premium” in Legimi-Apps auf:
Ähnliche
PREFACE
In recent years, outdoors activities and sports such as Nordic walking, trail running, hiking and swimming in the sea have developed considerably, especially during the health crisis. The practice of swimming in the sea regularly throughout the year has recently gained new followers. For swimmers, this means swimming regardless of the season, weather or water temperature, and which generally means swimming in cold water. Not just a quick dip as is common in Nordic countries or a short sprint in the increasingly popular icy water competitions, but a prolonged leisurely swim in water between 10 and 14°C.
This is what Nicolas Iconomidis has been doing for over 30 years. This activity provides regular swimmers with a state of physical and mental wellbeing. These benefits on physical and mental health have been well demonstrated in some situations. In other cases, it is said that the benefits are probable, given that studies in this field can be difficult to carry out. However, prolonged swimming in the sea in cold water also has its risks and constraints and can sometimes lead to antagonistic physiological responses. If the benefits outweigh the risks, a good knowledge and understanding of these benefits and risks allows the practice of regular swimming in safety. In this book Nicolas Iconomidis shares his personal experiences but he has also collected the testimonies of many swimmers who, like him, swim every day regardless of the weather in the Marseille area. They swim most often without a wetsuit in the Mediterranean Sea which, in the winter months, has an average temperature of 13°C. He explains in a detailed, yet comprehensive way, the physiological mechanisms of immersion, prolonged swimming and adaptation to thermal stress and the risk of hypothermia. This book offers recommendations to make this activity safe for both beginners and experienced swimmers. It will allow everyone to manage their practice by understanding the benefits and risks. After all, we only manage well what we understand well.
Doctor Jean Pierre AUFFRAY University Professor, President of the French Society of Maritime Medicine
Table of Contents
HISTORY
INTRODUCTION
I - IMPORTANT POINTS TO KNOW BEFORE SWIMMING
The temperature of the water
The state of the sea: currents, swell, and marine pollution
The main stinging sea creatures
The boats
The risk of infection
II - SWIMMING IN COLD WATER
Basics of human physiology
Physiological effects of immersion
Physiological effects of swimming
Physiological effects of cold water
Physiological and pathophysiological effects of swimming in cold water
III - COLD WATER ACCLIMATIZATION
Adipose tissue
Physical condition
Training
The cold shower
IV - HEALTH AND SWIMMING IN COLD WATER
V- STARTING TO SWIM IN COLD WATER
Tips
At the water's edge
Before swimming
While swimming
After swimming
VI - RECOMMENDATIONS FOR EXPERIENCED COLD WATER SWIMMERS
The preliminary medical consultation
At the water's edge
Over long distances
In case of prolonged interruption of swimming in cold water
Warming
VII - SWIMMING IN VERY COLD WATER LESS THAN 10°C
Water between 10 and 5°C
Ice water between 5 and 0°C
VIII - COLD WATER SWIMMING IN TRIATHLON AND SWIMRUN EVENTS
IX – SWIMMING IN ROUGH SEAS
X- WARMING UP AFTER SWIMMING
XI- GETTING THE RIGHT EQUIPMENT
For the safety and comfort of the swimmer
To avoid cooling at sea
In case of strong swell or current
To identify cooling
To avoid afterdrop
XII - QUESTIONS AND ANSWERS ABOUT SWIMMING IN COLD WATER
XIII - WEBSITES FOR SWIMMERS
XIV - CONCLUSION
XV - REFERENCES
ACKNOWLEDGEMENTS
SUMMARY TABLES
HISTORY
Before swimming in a pool, our ancestors swam in the sea, lakes or rivers. Nowadays, hundreds of thousands of people find the pleasure of swimming in the open air, in complete freedom. But there are risks linked to this that we must be aware of for our safety.
The birth of open water swimming refers to a love story from Greek mythology in Asia Minor between Hero and Leander. Hero, priestess of Aphrodite, lived on the European coast of the Hellespont and Leander on the Asian coast. Every night, Leander swam across the Dardanelles Strait to join Hero, who guided him in the night with a lantern from the top of a tower. Unfortunately, one night, the wind blew out the signal light and Hero found Leander dead in the early morning on the shore of the Hellespont and committed suicide from the top of the tower. Today, Leander's Tower is an ancient lighthouse on a small tourist island at the entrance to the Bosphorus in Istanbul.
The modern era of open water swimming, as opposed to bathing, probably began on May 3, 1810, when Lord Byron swam several miles across the Dardanelles from Europe to Asia.
Jason Zirganos, 46 years old, from Volos in Greece, was a pioneer of long-distance swimming in cold water. He crossed the English Channel in 18 hours and 45 minutes in 1949 and the Bosphorus in 4 hours in 1953 in water at 8°C. Unfortunately, he died in 1959 of heart rhythm problems 3 miles off the coast of Scotland while trying to swim across the North Channel (Ireland to Scotland) over a distance of 35 km in water between 9 and 11°C. This sad accident illustrates the dangers of swimming in cold water over very long distances. The death of this excellent swimmer is most probably due to a deep hypothermia responsible for these heart rhythm disorders.
INTRODUCTION
Why this book?
Swimming in cold water in winter is very popular, particularly in the south of France because of our favorable climate, but also especially due to its probable beneficial effects on well-being, health and hypothetical improvement of longevity.
The viral pandemic of Covid-19 in 2020-2021 has led, due to the closure of swimming pools, new and numerous people to swim in winter in the sea, lakes or rivers without really knowing the risks to which they are exposed. It is an easy activity to access as long as you live near a body of water; it also requires little equipment. Nevertheless, it is an extreme physical activity because of the exposure of the whole body to cold water which can cause important physiological modifications, but also fortunately, in the medium and long term, adaptive responses because some regular winter swimmers manage to acclimatize to cold water to varying degrees. The problem is to know if this activity really has beneficial effects or if it can cause harmful effects.
The purpose of this book is to provide information to swimmers about the human physiology of cold water swimming so that they know the benefits and risks of this activity in this extreme environment. It is also important that swimmers understand this natural environment and develop common sense to recognize and avoid risky situations and thus enjoy their passion safely. All the information in this book has been gathered from scientific publications to provide practical applications that everyone can use in their regular activity as a cold water swimmer.
I would like to greet our friends who swim in cold water in the Atlantic Ocean, the North Sea and the English Channel. They will find in this book a lot of information on the physiology and the physiopathology of winter swimming as well as advice and recommendations which I hope will be useful to them, without of course addressing all the problems specific to their natural environment, such as the marine fauna, the currents, the tide or the temperature of the sea water.
The International Winter Swimming Association (IWSA) has classified the sporting events according to the water temperature into three categories: cold water (between 5.1° and 9°C), very cold water (from 2.1° to 5°C) and icy water (from -2° to +2°C) and limits the maximum distance respectively to 1000 m for cold water, 450m for very cold water and 200m for icy water
The IWSA board decided to cancel the world championship in Petrozavodsk in Karelia (Russia) in 2022. Therefore, the Winter Swimming Championships will be postponed in january 2023 in Bled, Slovenia.
Nevertheless, most winter swimmers swim in water between 6° and 15°C and it is important to know that our perception of the water temperature is a function of the air temperature.
The passion for the sea and for swimming in cold water, which I have been practicing for more than 30 years in Marseille within my club "le Cercle des Nageurs de Marseille", led me to propose as a subject for a university diploma in emergency marine medicine in September 2020: "The hemodynamic and thermal effects of swimming in cold water".
I was thus able to apprehend during this work carried out from a small sample of swimmers of the club, not only the variations of blood pressure, pulse and temperature following the exposure of the body to cold water but also all of the physiological effects. Then it seemed interesting to us to have additional information on the state of health of these unusual swimmers, in particular those who have been practicing for several years with and without wetsuit, in order to know their physical characteristics, the average duration of swimming, their comorbidities1 or their susceptibility to winter infections. In December 2020, we conducted a survey of cold water swimmers in the Marseille, La Ciotat and Cannes coasts. The participants were informed beforehand, and their data was anonymized and destroyed after the end of the survey.
The analysis of these results sheds light on the profile of these athletes. There are 29 people (19 men and 10 women) who swim every winter at sea without wetsuits. The average age of the men is 60 years (the youngest is 42 years old and the oldest 84 years old) while the average age of the women is 53 years (the youngest is 28 years old and the oldest 68 years old). The men and women are rather tall (respectively 1.80m and 1.72m) with a normal average body mass index of 23.6 kg/m2 for the men (extremes 22.1 and 29.5 kg/m2) and 22 kg/m2 for the women (extremes 17.9 and 25.1 kg/m2). Most of them swim in winter at least three times a week (41%) or even every day (24%) and most of them (82%) stay more than 20 minutes in the water. When they get out of the water, they feel good (79%), which accompanies them for the rest of the day (72%). Nervousness, sadness and stress are correlated with the absence of a swim and half of the swimmers say they cannot do without a regular swim in cold water. In this survey, 65% of the swimmers were not taking any medication and 62% had no comorbidity. 81% of the swimmers did not smoke and one out of two consumed alcohols in moderation (i.e., 2 drinks or less in a day for man and 1 or less for women or non drinking). Another sport activity was found in 75% of the subjects, mainly cycling or hiking. The incidents that occurred in this small series (Fig.1) were mainly ENT (seven swimmers complained of tinnitus or dizziness and one presented an exostosis2), cardiovascular (three swimmers presented respectively a malaise, a hypertensive flare3 and a swimming-induced pulmonary edema4 and finally three swimmers after a swim of more than 60 minutes in an average sea temperature around 13°C presented moderate to medium signs of hypothermia5.
We can conclude from this series that this is a sport activity that is of interest mainly to 50–60-year-olds with a normal morphotype, non-smokers with moderate alcohol consumption, with few comorbidities and who also practice hiking or cycling. The immediate incidents are, during swimming, cardiovascular and especially ENT, and beyond half an hour of swimming, risks related to the installation of hypothermia.
Fig.1Incidents occurred in our group of swimmers during the cold swim (n=29). More than 50% were ENT, less than a quarter related to hypothermia or cardiovascular disease.
1 Comorbidities : Means more than one disease or condition is present in the same person at the same time.
2Exostosis: bony growths (in this case of the external auditory canal).
3 Hypertensive flare: severe elevation of blood pressure.
4 Swimming-induced pulmonary edema: extravasation between the capillary and the pulmonary alveolus with alveolar flooding of blood or protein fluid.
5 Hypothermia: core body temperature below 35°C.
I – IMPORTANT POINTS TO KNOW BEFORE SWIMMING
- The temperature of the water at sea.
When swimming in winter, it is essential for the swimmer to know the temperature of the water in order to determine beforehand the duration of the swim in the sea. You can get information about the sea surface temperature in Europe on websites (for example www.seatemperature.org/europe). This temperature can also be measured by a sport watch or a simple pool thermometer, which can be fixed in the water on a buoy or attached to the side of a ladder, sheltered from the swell.
In winter in the south of France, the average sea temperature ranges from 11° to 13°C and can sometimes drop lower especially around the Gulf of Lion. (Fig.2). The very cold surface water predominates at the bottom of the gulfs. This is the consequence of convection phenomena following the frequent winter gales (mistral and tramontane) associated with the arrival of fresh and cold continental water mainly by the Rhone.
In North Sea, the average sea temperature is colder in winter around 6 to 10°C depending on region and yearly variation and in the summer around 15 to 20°C.
In summer in the Mediterranean, when seawater temperatures vary between 20° and 26°C (Fig.3), these gales bring up cold deep water by destroying the surface layer. Near the coast, depending on its orientation, the wind can also push the warm surface water layer offshore and "pump up" cold deep water. This phenomenon, called́ the "upwelling", is especially sensitive in the Gulf of Lion. It is not uncommon in summer to see the temperature drop suddenly for a few days of about 10°C.
The thermocline is the narrow band separating warm surface waters from cold deep waters. In this zone, the temperature decreases very quickly. In the Mediterranean, there is a seasonal thermocline. In summer, the water temperature is constant up to a depth of about 20 meters, it is warmed by the air temperature and solar radiation, then it drops rapidly and stabilizes at 13°C.
Fig. 2Surface temperature in winter in the Mediterranéan Sea (according to nautical instructions).
Fig.3Surface temperature in summer in the Mediterranéan Sea (according to nautical instructions).
When autumn arrives, the surface water cools down and its density increases. It sinks, mixes with the deep waters and the temperature becomes homogeneous over the whole depth. The thermocline disappears. It is formed again as soon as the surface water warms up in spring.
In addition, the Mediterranean coastline presents the majority of the known karstic submarine springs in the world. Thus, sea water can be cooled in summer as well as in winter by these submarine fresh water springs of the limestone countries which can be found in France, in the Maritime Alps or in Provence, but also in Spain, Italy, Slovenia, Greece, Lebanon or Morocco.
- The state of the sea.
- Currents.
Rip currents are a major cause of accidental drowning on beaches all across the world. They can occur at any beach with breaking waves. It is a strong current that pulls the swimmer very quickly away from the shore. The best way to escape a rip current is to stay calm, don’t try to swim against it, roll on your back, raise your arm to signal for help, swim towards the breaking waves or parallel to the beach. Generally, rip currents subside 50 to 100 meters from shore. To avoid it when you first get to the beach, ask the lifeguard on duty for information on places where there are potentials rip currents or other hazards.
In seas with significant tides, tidal currents must be taken also into account as they can cause great risks for swimmers.
