Swimming in water that is 62°F (16.7°C) is certainly possible, but it requires caution and preparation far beyond a casual dip. This temperature places the water firmly in the cold category, meaning the human body will react strongly and quickly to the immersion. Understanding the physiological responses and having a safety plan is essential to transform a potentially dangerous experience into a manageable one.
Defining 62°F Water Temperature
Water at 62°F (16.7°C) is significantly colder than what most people consider a comfortable swimming temperature. For comparison, most heated swimming pools are maintained in the range of 78°F to 82°F (25.5°C to 28°C). The threshold for what is generally classified as “cold water” often falls below 70°F (21°C). At 62°F, the water is cool enough to trigger adverse physiological responses in an unacclimated individual, even though it is above the most dangerous range of 50°F to 60°F. This temperature is often described by experienced open-water swimmers as “fresh” or “nippy,” meaning it is suitable for swimming, but only with appropriate awareness and technique.
Physiological Impact and Immediate Safety Risks
The most immediate danger upon entering 62°F water is the cold shock response, which occurs within the first one to three minutes of immersion. This involuntary reaction causes an immediate, uncontrollable gasp reflex, followed by rapid breathing, known as hyperventilation. If the head is submerged during the gasp, a person can inhale water, which is a major cause of drowning in cold water incidents. Cold shock also dramatically increases heart rate and blood pressure, posing a risk of cardiac events, particularly for those with underlying health conditions.
Once the initial cold shock passes, the body enters the stage of cold incapacitation, where muscle function begins to degrade rapidly. This occurs because the body restricts blood flow to the limbs to prioritize warming the core, leading to a loss of manual dexterity and muscle power. Even strong swimmers may find their arms and legs becoming heavy and uncoordinated, making swimming difficult or impossible within minutes.
Hypothermia, a drop in the core body temperature below 95°F (35°C), is the long-term danger. In 62°F water, an average person might have hours before severe hypothermia sets in. However, the risk of drowning from cold shock or incapacitation is immediate.
Essential Preparation and Post-Swim Care
Safely swimming in 62°F water requires preparation, starting with appropriate gear to manage heat loss.
Gear and Safety
Using a wetsuit designed for swimming can extend the safe duration by providing an insulating layer of neoprene. Neoprene accessories like caps, gloves, and boots are important because the head, hands, and feet lose heat quickly due to the body’s circulation adjustments. It is highly recommended to never swim alone; utilize a buddy system or swim in a supervised area, and use a brightly colored tow float for visibility.
Entry Technique
The entry technique is important for mitigating the cold shock response. Instead of diving or jumping in, a slow, controlled entry allows the body to adapt gradually to the temperature change. Splashing water onto the chest and neck before full immersion can help desensitize the skin receptors and reduce the intensity of the gasp reflex. Swimmers should stay close to the exit point until their breathing rate is fully controlled and normalized.
Post-Swim Care
Post-swim care is essential due to a phenomenon called “after-drop,” where the core body temperature continues to fall even after exiting the water. This occurs because cold blood from the extremities returns to the core as blood vessels reopen for rewarming. To manage after-drop, swimmers must dry themselves immediately, remove all wet clothing, and dress quickly in multiple layers of dry, warm clothes, starting with the upper body and a warm hat. Consuming a warm, non-alcoholic drink, like hot chocolate or tea, helps warm the body from the inside. Avoid taking a hot shower or bath immediately after the swim, as rapid rewarming can accelerate the return of cold blood to the core, intensifying the after-drop and potentially causing faintness or nausea.