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Cold Water Swimming Revision Certificate

This revision certificate is provided for all who may have attended a Cold Water Swimming Information OR Introduction to Open Water Swimming Session with us OR swimmers who maybe trying Cold Water Swimming for the first time .

Anyone who is interested is welcome to read through the revision text and take the test,

Please read through the following information.

Once read, press the ‘Take Test’ link, please take your time and answer the questions carefully.


Thank you for making the time to refresh your Cold-Water Swimming understanding and safety practices. We believe that increasing cold water swimmers awareness of how individual’s respond to cold water immersion helps them achieve the most from their session whilst staying safe.  Response to cold can vary significantly from one person to another. 

Cold Water swimming -11 degrees Celsius and under is HIGH RISK. HIGH RISK to both Swimmers and Operators – we consider the benefits of Cold-Water Swimming phenomenal,  as a Water Safety team we relish cold water swimming and endeavour to make it a safe and popular Winter activity.

We are going to cover

1 A Swimmers physiological Response to Cold Water –  your bodies automatic reactions to a stimulus , in this case cold water swimming

2 Swimmer Good Practise – what you can do help yourself enjoy safe and effective Cold-Water Swims – what kit to bring

3   What we do as a venue Operator and Water Safety Team to ensure your safety whilst on site and in the water –

 4   Why do it / Health Benefits

1 Physiological Response / Your bodies automatic response to cold water

Whether you are an organiser considering offering winter swimming opportunities or a swimmer wishing to swim in cold water it is important that all understand how the body responds to immersion in cold water. Additionally, we should be aware of the problems associated with cold water immersion once you have exited the water

 Everyone’s body will differ slightly in speed and response to cold stimulus –

The effects of Cold-Water immersion happen in four key stages

•          Stage one – Cold Shock

•          Stage two- Cold Incapacitation/swim failure/peripheral cooling

•          Stage three – Hypothermia

•          Stage Four -After Drop

Stage One Cold Shock

Immediately after entering cold water your body goes through several reflexes (uncontrollable reactions. )

  • Immediate Gasp Reflex – deep breaths that fill the lungs and/ or followed by   very rapid and shallow out of control breathing
  • It becomes harder to hold your breath.

For the unwary, cold water shock can be fatal, especially if that sharp intake of breath occurs under water.

  • Vasoconstriction – Vasoconstriction is a normal process. It helps keep your body in healthy balance. In the case of rapid skin cooling narrowing of the blood vessels in the peripheries such as arms/ legs, hand and feet results in less blood flowing to the skin to help your body conserve heat. This in turn increases your heart rate and blood pressure as the vasoconstriction makes it harder work for the heart to  pump blood around the body.

A swimmer with an unknown underlying heart condition or high blood pressure may be in difficulties and runs a risk of  cardiac arrest, stroke, heart failure, respiratory failure.

  • Panic –As well as the physical response there could also be a reduction in the ability to think clearly which can result in disorientation and panic.

Cold Shock reactions generally last up to three minutes. It is important to remember that the cold shock response lasts longer as water temperature decreases and may last several minutes before breathing is stabilised.

Stage 2 – Cold Incapacitation/Swim Failure

 Cold Incapacitation is the cooling of peripheral tissues especially in the extremities i.e. hand and feet, leading to stiffness, poor coordination, impaired motor skills and loss of muscle power. In a swimming context this impacts on the ability to swim effectively, keep afloat/maintain regular body position , reduces  the ability to reach and grasp onto rescue aids and climb out of the water. It can also cause the excessive inhalation of water in rough conditions as it becomes more difficult to coordinate breathing with the swim stroke.

  • After the cold shock response, your extremities (hands, feet, arms and legs) start to cool down,  less blood circulates to the skin
  • As your arms and leg muscles get colder you have less flexibility, strength and stamina. This affects your physical ability.
  • Loss of coordination as we become cold .It is this loss of coordination that may cause  excessive inhalation of water as a swimmers ability to coordinate breathing with swim stroke is impaired.
  • Example ‘you get in, after a couple of minutes of feeling uncomfortable the water feels pleasant. You then begin to swim

Your body loses heat in water at an alarming rate approx. 25 time faster than in air Because you cannot generate more heat than you are losing especially if you are swimming in skins your body continues to lose heat, blood shunts to the core to keep organs warm. Your muscles lose power, limbs become slow, heavy, clumsy, and numb and obviously swimming becomes increasingly difficult. This is cold incapacitation and can easily lead to drowning.

  •  Swimmers limbs are clumsy and numb; you will struggle to grip with hands, stepping up and out of ramp can be wobbly /uncoordinated.

During the Swim phase please beware of other conditions that may arise ;

  • Cramp– cramp can strike anywhere, and some people are more prone than others. If you are cold, cramp is perhaps more likely. If you do cramp, float on your back. Hold your tow float and shout for Lifeguard. The life guard will be able to assist you to an exit point.
  • Asthma in some asthmatics, cold can trigger an attack. Please bring your named  inhaler, give to Registration Officer upon arrival.
  • Cold Water Urticaria; Cold urticaria is a skin reaction , hives (urticaria) or large red welts form on the skin after exposure to a cold stimulus. The welts are usually itchy and swollen . They will disappear when you are warmed up.

Stage Three – Hypothermia / Long Term- deep tissue cooling

As the body loses more heat than it can generate the deep tissues cool. Clinical hypothermia is defined as when the core temperature drops from the norm of between 36.5 – 37⁰C to 35⁰C or lower.

Symptoms of hypothermia can include: • constant shivering • tiredness • mental confusion • low energy • cold or pale skin ,fast breathing (hyperventilation)  ,Slurred speech  ,Poor muscle control

Hypothermia is a serious medical condition which can increase the risk of heart and respiratory failure.

Stage Four – After Drop

 The decline in your core temperature after you have got out of the water.

 The body continues to cool after it has exited the water – this is commonly referred to as “After Drop” and is due to the continued conductive cooling of the deeper tissues, until the temperature gradient is reversed i.e. until heat is donated to the core by the rewarming process – either warmed superficial tissues or active muscles. You are likely to experience the lowest core temperature around 20- 30 minutes after exiting the water.

Factors Affecting an individual’s Cooling Rate

There are a wide range of factors that affect the cooling rate for each individual. These include but are not limited to:

  • Age • Gender • Body morphology – including fat, muscle mass and body shape (tall and thin, short and stocky) • Water and Air temperature •Wind direction  Water movement • Fitness • Health • Fatigue • Alcohol consumption • Insulation e.g. wetsuit (and thickness of wetsuit) •

2 Swimmer Good Practise – what you can do help yourself enjoy safe and effective Cold-Water Swims – what kit to bring

Medical Screening- Cold water shock puts an enormous strain on the heart and increases blood pressure . It is a wise and responsible step to have an ECG and have a blood pressure check to ensure you do not have any unknown underlying condition prior to going cold water swimming.

Alcohol/Drugs Do not swim in cold water if you have consumed alcohol/under the influence of drink or drugs 

Fully Informed of Cold Water Effects on your body.- ie psychologically prepared ,

Habituation – The body adapts quickly. The more frequently your body is immersed in cold water the quicker it adapts. Cold Showers are useful between cold water immersions/swims

More often the easier/quicker your body adapts. Start short spells , cold showers , work through the four stages realistically ( give Stage Three Hypothermia a miss !) remember to give  yourself a margin of safety  when getting out i.e allowing for the after drop.

Wetsuit or Swimming Costume?

Wearing a wetsuit does not eliminate cold shock but it does provide additional insulation and therefore reduces the rate of cooling. However, this does not mean that swimming without a wetsuit is fundamentally less safe but that the acclimatisation process and time spent in the water may need to be adjusted. On this basis Lenches Lakes does not stipulate a compulsory wetsuit approach but does recommend the use of wetsuits particularly for swimmers who are new to winter swimming as they gain experience and develop an understanding of how they react to cold water.

There is a wide range of wetsuits available. Advice for new (winter) swimmers points to be considered:

• A full body wetsuit offers greater insulation than a shorty or sleeveless suit that increase the amount of exposed skin

• The thicker the neoprene the greater the level of insulation so it may be worth considering a thicker suit for winter swimming .

In all cases the wetsuit should be well-fitted and specifically designed for swimming. ie not a surfing wetsuit.

There are other items of kit made from neoprene that cover the extremities, helping to reduce the rate of cooling as well as numbness and pain experienced by some swimmers in cold water.

• Neoprene hats/ balaclavas

• Neoprene gloves and boots

Ear Plugs

Earplugs often help swimmers who may suffer discomfort from cold water in their ears such as dizziness, nausea and/or vertigo/balance impairment. Some swimmers consider them helpful to keep warm.

Tow Floats

Lenches Lakes ask all swimmers to use a tow float regardless of whether they are wearing a wetsuit or not in the winter. Whilst a tow float is not a life-preserver it can provide support for a swimmer in difficulty, it increases visibility of swimmer  and it provides the safety team with something to hold in the event of having to rescue a swimmer in difficulty .

Keep a record of your swims, temperatures and duration.

 It is a good idea not to set goals / be prepared to be flexible if your body reacts to the cold quicker than normal.

Consider your body type. As previously stated there are a wide range of factors that affect the cooling rate for each individual.

Cold Water Shock During the cold shock phase the main risks are:

  • Increased risk of breathing in water  by gasp response,
  •  Fast rapid and shallow out of control breathing / hyperventilation
  • Heart failure , stroke caused by the increased heart rate and blood pressure
  • Panic or inability to think clearly and make or carry out a strategy to self-rescue

These can be mitigated to a certain extent by:

  • Fuel your body – a light meal allowing one and half hours prior to swim –
  • Hydrate
  • Wearing a wetsuit
  • Be aware of the temperature- have you swum in that temp before? How did your body react ?
  • Immersing the whole body in the water slowly, allow time to acclimatise to the water temperature before swimming. Generally up to three minutes. During this acclimatisation the head should remain above water.
  • Wade in slowly is the safest preferred option- generally gasp and short breaths subside after a few minutes.  You will see experienced Cold Water Swimmers get in quickly either wading or diving and start to swim immediately to them this is their preferred option please remember they are experienced – it is their preferred option it may not be the best option for you.

Swimming should not be attempted until the swimmer has acclimatised to the temperature and their breathing has become regulated e.g. can they speak in full sentences

Stage Two – Cold water incapacitation /swim failure

During cold water incapacitation, the main risks are:

  • Swim Failure due to impaired motor skills and loss of muscle power
  • Difficulty in keeping afloat/regular body position
  • Difficulty in reaching and holding on – with implications for reaching and holding on to rescue aids or being able to self –rescue e.g. climbing out using steps

These can be mitigated to a certain extent by:

  • Carefully managing the time spent in the water so that you exit the water before the onset of cold  incapacitation
  •  Give your body chance to adapt
  • Never set time goals for staying in the water.
  • Get out if you are not comfortable.
  •  Being fully informed hence you become aware/monitor of your response to cold water;
  • Be are aware that your breathing is not normal,
  • Be aware of your own personal first signs of swim failure – numb fingers, wrists, feet numb , numb nose,
  • If you are disorientated -cognitive ability effected.
  • Lightheaded
  • Hands/fingers numb unable to control them – pincer grip test 
  • Limbs heavy
  • Struggle to speak / incoherent sentence
  • If you feel yourself slowing down or struggling to swim
  • Inability to float as you would normally.

The standard way to ask for help is by rolling onto back, holding tow float , shouting to lifeguard for assistance , the  lifeguard can assist you to exit, or accompany you as you swim to  exit point.

  • You have a choice of Swim circuits , 200m, 100m and 50 m. Simply ,the   shorter the swim circuit the nearer the Entry and Exit point . If in any doubt keep near the entry/exit point by swimming around the 50m circuit.
  • There are two Lifeguards on the water – they remain in close proximity of all swimmers they are there to help , not waiting for an emergency to happen, they are there to monitor individuals ,to prevent onset of swim incapacitation/failure , to prevent emergency situation as well as deal with emergency situation.
  • Always follow the instructions of the safety team and get out if they ask you to- they have your best interests at heart.

Stage 3 – Hypothermia

Clinical hypothermia is defined as when the core temperature drops from the normal of between 36.5 — 37⁰C to 35⁰C or lower. The symptoms include mental confusion, slurred speech, and poor muscle control. Hypothermia is a serious medical condition which can increase the risk of heart and respiratory failure.

An incredible 2 to 1.5 degree drop of core temperature results in hypothermic effects .

If a swimmer carefully monitors their initial signs of cold water incapacitation Hypothermia will be avoided.

Start with short swims to learn what your first signs of cold-water incapacitation are. If signs of cold water incapacitation are ignored you may find your stroke rate slows down , you start to shiver, or breathing rate changes. These are signs of hypothermia., you need to exit the water , reheat, seek medical support.

Stage 4 – After Drop  – to minimise the risk of after drop

Reheating or Rewarming needs to be carefully managed to mitigate risks and during this time swimmers should be monitored and deterred from driving or cycling. As a minimum the swimmers should be monitored for 1.5 times the period of cold exposure, aim for a minimum of thirty minutes after the swimmer has left the water. It can potentially take several hours before normal core temperature is completely restored.

Effective reheating ideally should take place in a sheltered warm environment.


  • Hats are key. Remove all wet layers. Get dressed quickly and warmly.  Start from the top half of your body. Multiple layers are preferable to a single layer. Put on a warm hat, gloves and thick socks. Immediately after swimming you will hopefully not be shivering , use this time wisely , dress quickly before ‘Reheat ‘shivering kicks in. Your core temperature will probably be at its lowest 20/30 minutes after exiting the water.
  • Shivering is your bodies method of generating heat
  • Sipping a  warm sweet drink  and eat a sugary snack . Shivering is a highly energy consumptive bodily function. You need to fuel it.
  • Don’t take a hot shower as this will increase the rate at which cooled blood returns to the core and makes the drop faster and deeper. Cold water swimmers have been known to faint in hot showers. Wait until you’ve warmed up again before showering/bathing.
  • Think your reheat through- what are you going to stand on whilst changing, take your swim hat off and put a warm hat on,- , how are you going to preserve your modesty whilst you take your wet clothes off/ put dry clothes on, the secret is speed , no nattering on lakeside before changing , natter and changing is great .
  • The essence is get out of the water,  get changed as quick as nickers, sip a warm sweet drink , if you are feeling good , start to generate some heat by walking  around lakeside, woodland.
  • Bring a hot water bottle to pop in with your clothes whilst you swim
  •  Bare cold skin should not be exposed to very hot air or surfaces (e.g. radiator or

uninsulated mug) due to the increased likelihood of developing chilblains.

  • Re-warming should be gradual.
  • Do not use foil space blankets to try and warm a cold swimmer. Cold swimmers do not radiate heat so there is no heat for the foil blankets to trap and reflect.  Sleeping bag
  • Keep an eye on fellow swimmers. Someone who appears completely fine getting out of the water may be in trouble 20/30 minutes later and may need your help.
  • Get out of the water before you get too cold as you will continue to get colder after swimming- give yourself a margin a safety.
  •  If you do have to rush off be aware what your body is doing, do not drive- have someone drive you. Cognitive and motor skills may be affected by after drop i.e core temperature dropping to hypothermic

3   What we do as a venue Operator and Water Safety Team to ensure your safety whilst on site and in the water

  • Ensure all staff are fully trained and received continued frequent specialised Cold-Water training.
  • Provide all lifeguards with warm wetsuits and additional gear to keep them warm in all weather conditions enabling prompt action,
  • Provision of Kayaks to enable fast emergency response  and close proximity to swimmers at all times.
  • Lifeguards come off the water and have a warm up 30 minute break every 60 minutes
  •  AED on site ensuring in the case of Cardiac arrest prompt action.
  • Ask all swimmers to attend a Cold Water Information Session-/complete online revision certificate – all swimmers fully informed.
  • Provide Swimmer Passports – medical details , emergency contact , record the temperature both air and water and duration of your session – Signed by Registration Officer . Allow us to monitor your progress – give you official temps for entry to events  .
  • Provision of shorter swim circuits.
  • Provision of warm room
  •  Benefits of Cold-Water Swimming

  Reduce Stress – can help our bodies deal with stress.

Improves circulation

Boost immune system

Increases libido

Feel Good/Natural High/Post swim high

Improves mood /positive effective on mental wellbeing.

Burns calories /increase metabolic rate