Sauna Bathing Habits and Erectile Dysfunction-Tampere Ageing Male Urologic Study (TAMUS)

Introduction

Erectile dysfunction (ED) is common and the prevalence of ED in-creases with age. Prevalence ranges from 2-9% for ages below 40 years old to 10-71% for 70 years old or older and 18-86% for men aged 80 years or older [1]. Sauna has an important part in the Finn¬ish and the Nordic culture. In sauna, water is thrown to hot rocks on a stove to generate steam. Finnish sauna is less humid than many other saunas, as relative humidity is between 10% and 20% and temperature from 80°C to 100°C. In Finnish sauna, one sitting period takes 5-20 minutes at a time, often repeated several times. A cold shower or water plunge commonly follows sauna [2].

The exact mechanism how sauna bathing seems to relieve different conditions is not known. One theory is that sauna bathing increas¬es nitric oxide (NO) bioactivity [3]. A similar mechanism is also used in ED medication [4]. Therefore, it is worth of investigation if sauna affects erectile function. To our knowledge, an association between ED and sauna bathing has not been investigated earlier.

Materials and Methods

This report is part of the Tampere Ageing Male Urologic Study (TAMUS). Material for this study was collected in 2019 as a postal questionnaire was sent to the target population following a remind¬er questionnaire after three months to men who had not responded to the initial one. The target population comprised men born in 1924, 1934, 1944, 1954, 1964 or 1974 who resided in Tampere or 11 surrounding municipalities. A similar protocol was used for this study as for previous TAMUS surveys [5,6].

Questionnaire included questions concerning basic demographic information, details about health-related issues e.g. history of diag-nosed diseases, possible operations and use of medications.

Sauna bathing habits was evaluated with the following question: “How often do you sauna bath?” with the response alternatives: “not at all”, “once a month or less”, “once a week”, “two times per week or more”. For the analysis, those reporting no sauna bathing or bathing once a month or less groups combined, as these repre¬sented minimal sauna bathing in the Finnish context.

ED was evaluated using the validated International Index of Erec¬tile Function (IIEF-5) questionnaire [7]. Five questions were: “How do you rate your confidence that you could get and keep an erection?”, “When you had erections with sexual stimulation, how often were your erections hard enough for penetration?”, “During sexual intercourse, how often were you able to maintain your erection after you have penetrated your partner?”, “During sexual intercourse, how difficult was it to maintain your erection to completion of intercourse?”, “When you attempted sexual in-tercourse, how often was it satisfactory for you?” Every question had five answering alternatives: “very low”, “low”, “moderate”, “high” and “very high” scored as 1-5 points per question. As the points were summed up, the total score represented erectile dys-function. A score 22 -25 indicate normal erectile function, 21 – 17 mild ED, 16- 12 mild to moderate ED, 11-8 moderate ED and 5-7 severe ED. Men using medication for ED were asked to fill out the IIEF-5 questions twice: with and without medication.

Use of medication for ED was assessed for the past five years. The treatments modalities were divided into oral medication and in¬jections. Testosterone replacement therapies were included in the analysis as ED treatment.

To evaluate the possible differences between the medications, IIEF-5 questionnaire with medication was used. Two-sided chi-square test was used to assess statistical significance of associa¬tions. Ordinal regression analysis was used to estimate odds ratios and the confidence intervals. SPSS (Statistical Package for Social Sciences) version 27.0 was used in the data analysis.

The Tampere University Hospital Committee for Research Ethics approved the study protocol (tracking number #99050).

Results

The response proportion was 47.8% as 2,644 out of 5,537 men returned the questionnaire. Most men reported sauna bathing once a week (40%), although almost similar proportion of the men used sauna two or more times per week (36%). Men reporting sauna bathing once per month or less comprised a fifth (22%) of the study population, including 167 men (6%) reporting no sauna bathing at all.

In terms of demographic characteristics, the average ages of the sauna bathing groups, were comparable, around 63 years (Ta¬ble 1). Frequent sauna bathers were more often cohabiting and smoked less. Men with university degree were over-re-presented in the least frequent sauna bathing group and those with intermedi¬ate stage education in the most frequent sauna bathers´ group. Fre¬quent sauna bathers reported a previous diagnosis of depression or diabetes less frequently than the other groups. No clear differences were seen in other chronic diseases or operations, which could in¬fluence to development of ED.

               Table 1: Demographic Characteristics Of Study Participants According To Sauna Bathing Frequency

The mean IIEF-5 scores were similar across sauna bathing groups (Table 2). However, men sauna bathing two or more times per week reported more frequent sexual intercourse than those with less sauna bathing men: the average number of intercourses per month was 3.5 (95 CI 3.2-3.8) among men sauna bathing twice or more per week versus 2.8 (95% CI 2.5-3.0) among men sauna bathing once a week and 2.5 (95% CI 2.2-2.9) for men with less sauna bathing.

The mean IIEF-5 scores when ED medication was used were also similar regardless of sauna bathing frequency (Table 2). The find¬ings were similar for the whole study cohort and the men reporting use of ED medication. As different categories for severity of ED were compared, mild ED was less common in the group with the most frequent sauna bathing (21.7%) than among men with less sauna bathing (26.8% and 29.3%).

                                                                      Table 2: Erectile Function According To Sauna Bathing

However, no association between prevalence of ED and frequen-cy of sauna bathing was found (OR 0.05, 95% CI -0.18-0.84 p=0.474). Older men, men living alone or men having history of diabetes, elevated blood pressure, depression, high cholesterol levels and radical prostatectomy had statistically significant risk elevation (mostly OR 0.3 – 0.6) for ED.

Use of ED medication did not materially differ between sauna bathing groups (Table 3). Frequent sauna bathers seemed to use more oral ED medications, but no statistically significant differ¬ence was demonstrated.

                              Table 3: Treatment for ED in last 5 years According To Sauna Bathing Frequency

Discussion

Sauna bathing has been reported to influence positively several medical conditions and physiological processes. The mechanism for such effects remains unknown, but a potential candidate is ni¬tric oxide, which is also used for treatment of ED. Therefore, it is reasonable to study if there is connection between sauna bathing and ED. We are not aware of any previous studies concerning the relation between the sauna bathing and ED. In our study, we did not find any evidence of long-term effect of sauna bathing on ED development, although more frequent sauna bathers reported more intercourses than the men sauna bathing only once a week or less. Furthermore, they also used more oral medication for ED. These findings could be explained by active lifestyle of frequent sauna bathers.

Previous research suggests that regular infrared and/or Finnish sauna bathing may provide beneficial effects particularly with cardiovascular and rheumatological diseases [8]. Sauna bathing may decrease the risk of vascular diseases, neurocognitive diseas¬es, pulmonary diseases and also other conditions such as arthri-tis, headache and flu [3]. The possible mechanism underlying the health effects of sauna bathing effects is not known but multiple different pathways have been proposed to be responsible for ef-fects.

It has been suggested that heat stress in sauna induces changes in molecular mechanisms that protect the body from damage, similar to those provoked by exercise, which may forestall the effects of aging [9]. One molecular theory is that the positive effect of sauna bathing is caused by an increase in nitric oxide (NO) bioactivity.3 This is an interesting theory for our study, because for treatment for ED, a specific phosphodiesterase type 5 (PDE 5) inhibitor is used to enhance nitric oxide (NO) mediated vasodilation in the corpus cavernosum by inhibiting cyclic guanosine monophosphate breakdown [10].

Sauna bathing can have also negative effects. One study demon-strated impaired spermatogenesis associated with sauna bathing 15 minutes twice a week but the changes were normalized in six months after the exposure was stopped [11].

In our study, the prevalence of ED was comparable to other stud¬ies. Prevalence varied considerably from study to study as among around 70 years men prevalence vary between from 10 to 71 per¬cent [1]. In our study cohort with a mean age of 63 years, 19 per¬cent of men reported at least mild to moderate ED.

Sauna bathing frequency was not associated with the mean IIEF-5 score or prevalence of ED.

Seeking help for ED could have significant differences between different cultures. Therefore, significant differences could be found between studies concerning prevalence and treatment of ED. Main reasons for delayed help seeking has shown to be embarrassment and thinking of ED as a natural process of aging [12]. Total of 14.8 percent of men in our study cohort reported having received treatment for ED in the last five years. In UK, longitudinal study including 1162 men with mean age of 59 years were conducted and 37 percent of them receive treatment for ED at the baseline of the study, which was more than in our study [13]. More fre-quent sauna bathers were also more prone to use medication for ED, but there was no statistically significant difference between sauna bathing groups.

Treatment for ED was compared according to sauna bathing fre-quency and was similar between groups. Mainly oral medication was used as expected in a population-based study.

Sauna bathing frequency was not associated with subsequent ED, unlike age, diabetes, hypercholesteremia, elevated blood pressure, depression and a history of radical prostatectomy which are known risk factors for ED [14-16].

Education seemed to have preventive effect to ED in our study cohort, however it was slightly not statistically significant. The more educated men were, the less likely they had ED. A hypothesis could be made that less sauna bathers have less ED as they were more educated, but this was not the case. On the other hand, fre¬quent sauna bathers smoked less and had less diabetes and depres¬sion, nevertheless the sauna bathing groups had the same erectile function. These factors could interpret that sauna bathing could also have a negative effect to erectile function.

Men sauna bathing frequently also reported more frequent sexu¬al intercourse. This is likely explained by the fact that they were more often married of cohabiting than men with less sauna bath¬ing, so they had probably more opportunities for intercourse.

As this was population-based postal questionnaire study, our re¬sults demonstrated findings from “normal” life. One shortcoming was that sauna bathing sessions was not standardized. To evaluate sauna bathing in a standardized fashion would require information on duration of each sauna session and ideally more detail about condition in sauna such as temperature and humidity. In 1994, the initial TAMUS questionnaire assessed the exact number of sauna bathing times per week [17]. The number of men sauna bathing more than twice per week was small and therefore in the 2019 questionnaire, sauna bathing frequency was divided into four cat¬egories (none, once a month or less, once a week and two times per week or more). In our opinion, this division was reasonable in this population-based setting. It could be interesting to collect data from men sauna bathing very frequent, like every day to evaluate if major exposure to sauna bath has any difference to results.

Conclusions

Sauna bathing frequency was not associated with ED in our pop¬ulation-based cohort study. There were no differences in IIEF-5 scores or use of medication for ED between the groups according to sauna bathing frequency. Yet, frequent sauna bathers reported sexual intercourses that are more frequent and had fewer risk fac¬tors for ED.

Author Contributions

Antti Pöyhönen: No conflicts

Jonne Åkerla: No conflicts

Anssi Auvinen: Lecture fee Amgen/Janssen

Teuvo LJ Tammela: paid consultant to the company Astellas, Am-gen and Janssen-Cilag.

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