Reference; https://mbp-japan.com/jijico/articles/32488/
Modified and translated by CFJA
A Dangerous Lifestyle Habit That May Contribute to Low Blood Pressure: Going to Bed Immediately After a Hot Bath!
Based on my many years of clinical experience, I believe that low blood pressure is closely associated with bathing habits. (*In Canada, similar concerns may apply to activities such as sauna use and hot yoga.)
In my clinical experience, many people with low blood pressure tend to have a slender build, a sensitive digestive system, and a tendency to feel cold, particularly in their hands and feet. As a result, they often try to warm their bodies by adopting the following habits:
Taking long, hot baths.
Going to bed immediately after bathing.
Some people develop these habits as early as their teenage years.
Prolonged exposure to hot water can cause an excessive increase in core body temperature. If a person gets into bed before sweating has subsided and the body has released excess heat through the hands and feet, heat may remain trapped in the body. This can interfere with the natural decline in core body temperature that is necessary for falling asleep and maintaining deep, restorative sleep. As a result, sleep quality may deteriorate.
Poor sleep quality may interfere with the nighttime recovery and regulation of the autonomic nervous system and internal organ functions. Over time, this may disrupt the body’s physiological balance and contribute to reduced physical strength and vitality.
In addition, inadequate sleep may affect the body’s normal autonomic responses upon waking, including sympathetic nervous system activation, potentially making it more difficult for blood pressure to rise appropriately in the morning.
If these habits continue over a prolonged period, digestive function and appetite may decline, potentially reducing energy intake and contributing to increased sensitivity to cold, especially in the hands and feet. This may create a recurring cycle of fatigue, poor appetite, and cold extremities. ❷❸
From this perspective, regularly going to bed immediately after a prolonged hot bath may be an unhealthy lifestyle habit that gradually affects overall health without the individual realizing it. Although a direct link to shortened lifespan has not been established, the potential effects on sleep quality and physical well-being should not be overlooked.
Arrhythmias: A Possible Warning Sign of Stress on the Heart
When you immerse yourself in a hot bath, your body temperature rises, your blood pressure may initially increase, and your heart rate becomes faster. People with low blood pressure often report feeling comfortable and refreshed after bathing.
For this reason, some people develop the habit of going to bed immediately after bathing because they want to:
a. Prolong the pleasant feeling they experience after bathing.
b. Rest their bodies while they still feel comfortable and relaxed.
c. Enjoy a comfortable and restful night’s sleep.
However, I believe that this habit may place additional stress on the cardiovascular system and potentially contribute to problems with blood pressure regulation.
Immediately after a hot bath, the body may still be in a physiological state resembling that experienced after physical exercise, with an elevated heart rate and increased body temperature. Going to bed immediately afterward means attempting to rest while the cardiovascular system is still adjusting to these changes.
Although the body can generally adapt to occasional changes in cardiovascular activity, repeatedly exposing it to prolonged heat and then going directly to bed may affect autonomic nervous system regulation, particularly in susceptible individuals.
Some people may experience arrhythmias, or irregular heartbeats. When the heart’s pumping function becomes impaired, blood circulation to vital organs, including the brain and kidneys, may be affected. This can contribute to symptoms such as those described in items 1) through 7).
Based on my clinical experience, I believe that regularly going to bed immediately after a hot bath is a lifestyle habit that deserves attention, particularly among people with low blood pressure or existing cardiovascular conditions.
Medical accuracy note: The proposed relationship between going to bed immediately after bathing, cumulative heart fatigue, arrhythmias, and chronic low blood pressure has not been conclusively established by scientific research. Arrhythmias can have many causes and should not automatically be attributed to bathing habits.
References
❶ Low Blood Pressure (Hypotension)
Drug Information Center, Aichi Pharmaceutical Association
低血圧 | 薬事情報センター | 一般社団法人 愛知県薬剤師会
❷ Healthy Sleep and Lifestyle Habits
e-Health Net, Health Japan 21 Action Support System, Ministry of Health, Labour and Welfare, Japan
厚生労働省 健康日本21アクション支援システム（e-ヘルスネット）「快眠と生活習慣」
❸ Sleep and Body Temperature
Terumo Body Temperature Research Institute
テルモ体温研究所「睡眠と体温」