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High scrotal temperatures and chairs in the pathophysiology of poor semen quality
Abstract
AIM:: The purpose of the present study was to investigate the temperature and humidity of the scrotal skin during sitting on commonly used chairs in relation to body mass index. MATERIALS AND METHODS:: Six different chairs were studied, and 8 men participated in the study. In addition to traditional sensors also infrared photography was used in recordings. RESULTS:: Statistically highly significant increase up to 3 degrees C was recorded when subjects were sitting on commonly used chairs already in 20min. When the subjects were sitting on the saddle chair no increase of scrotal skin temperature or humidity was observed indicating good ventilation due to open hip and knee angles. Body mass index correlated with the scrotal skin temperature, when the subjects were sitting on the conventional cushioned office chair, but not when sitting on the saddle chair. Chairs which increase the scrotal temperature may have contributed to the decrease of semen quality and quantity reported during the last decades in sedentary societies.
... The transfer of heat from the human body to its surroundings is resisted with thermal insulation materials or the variation of heat dissipation area in the scrotal skin; clothing insulation (Zorgniotti et al., 1982;Mieusset et al., 2007), posture when standing, sitting or in a supine position (Rock & Robinson, 1965;Mieusset et al., 2007), the angle between two legs at a sedentary posture on a chair (Brindley, 1982;Mieusset et al., 2007) and the style of the chair (Koskelco et al., 2005). ...
... However, they did not compare ambient temperature and chair cushion thickness with scrotal temperature. Koskelco et al. (2005) compared the effect of six different chairs including cushioned and non-cushioned chairs, and reported that the SST did not increase while on the saddle chair. However, they did not include the variations in the chair's cushion thickness and ambient temperature. ...
... The SST was significantly affected by air conditioning temperature (p < 0.001), but was not statistically correlated with the chair's cushion thickness. Koskelco et al. (2005) reported that the scrotal temperature was higher in the cushioned chair (34.3°C) than in the non-cushioned chair (33.7°C) statistically. They designed the experimental boundary for the static posture with the subject reading literature and using a belt, with the ambient temperature at 23°C and relative humidity at 28% (it seemed they did not control humidity in the winter season). ...
The hypothesis of this study is that the air conditioning temperature and thickness of the chair cushion affect a man's scrotal, and consequently testicular, temperature. Ten healthy male subjects volunteered for the study (age: 23.4 +/- 2.4 years; height: 173.8 +/- 5.09 cm; weight: 71.6 +/- 9.7 kg; body fat ratio: 18.6 +/- 4.1%). The air conditioning temperature was controlled at 18 degrees C to represent the heating season, and at 26 degrees C to represent the cooling season. The thickness of the chair cushions was varied from 0 to 8 cm at 2 cm intervals. The changes in the scrotal surface temperature (SST) and buttock skin temperature were measured for 120 min. At the ambient temperatures (t(a)) of 18 and 26 degrees C, the average SST were 33.76 +/- 1.28 and 35.02 +/- 0.54 degrees C for the chair cushion thickness (C(thk)) of 0 cm, 33.87 +/- 1.07 and 34.96 +/- 0.75 degrees C for C(thk) 2 cm, 33.91 +/- 0.84 and 35.03 +/- 0.85 degrees C for C(thk) 4 cm, 34.42 +/- 0.89 and 35.02 +/- 0.63 degrees C for C(thk) 6 cm, and 34.65 +/- 1.21 and 34.99 +/- 0.62 degrees C for C(thk) 8 cm respectively. SST was significantly affected by the air conditioning temperature (p < 0.001), but was not statistically correlated with the chair cushion thickness.
... In a study comparing the increase in scrotal temperatures while seated on different types of chairs, Koskelo et al. [ 62 ] reported a 3 °C increase in scrotal temperature upon 20 min of sitting on a conventional cushioned offi ce chair. However, they found no difference in temperature when subjects sat in a saddle chair. ...
... However, they found no difference in temperature when subjects sat in a saddle chair. This is probably due to the open hip and knee angles, which allow for adequate scrotal ventilation [ 62 ]. Similarly, sitting with crossed legs causes a bigger increase in scrotal temperature than sitting with the legs apart (at an angle of about 70°) [ 63 ]. ...
Testicular temperature is reflected by the temperature of the overlying scrotum. The scrotum is well placed anatomically and is capable of physiologically maintaining a hypothermic testis. However, when normal thermoregulation of the testis is impaired, heat stress can occur, negatively effecting semen quality and sperm concentration, motility, and morphology. A number of factors can disturb thermoregulation and increase testicular temperature including pathological conditions such as varicocele and cryptorchidism, posture, clothing, common lifestyle choices such as use of saunas and warm baths, certain exercises such as cycling, laptop usage and occupations that involve or generate heat, and raised ambient temperature. Often, these factors do not occur alone but in combination with one another, which compounds the negative effect of high testicular heat levels on semen parameters. This chapter discusses physiological thermoregulation in the testis, the impact of its failure on semen quality and enumerates factors that could simultaneously and cumulatively contribute to testicular heat stress. Awareness of the potential risks involved and methods to alleviate prolonged scrotal warming are important in the preservation of male fertility. Simple changes to daily habits could help lessen the impact of increased testicular temperatures on male fertility.
... It is interesting to consider which pathomechanism could be responsible for sperm DNA damage in 'sedentary' men. It has been shown that a sitting position may lead to testicular heat stress [20,38,39], which may provoke DNA damage [21-24, 40, 41]. As reported by Koskelo et al. [38], only 20 minutes of sitting in an office chair can increase the scrotal temperature by up to 3˚C. ...
... It has been shown that a sitting position may lead to testicular heat stress [20,38,39], which may provoke DNA damage [21-24, 40, 41]. As reported by Koskelo et al. [38], only 20 minutes of sitting in an office chair can increase the scrotal temperature by up to 3˚C. Moreover, Bujan et al. [39] observed that the mean scrotal temperature increased in drivers after 2 hours of driving, reaching a value 1.7-2.2˚C ...
Introduction. Contemporary professional jobs that often enforce a sedentary lifestyle and are frequently associated with testicular overheat, deserve special attention with respect to male fertility potential. Interestingly, the harmful effect of testicular heat stress on sperm characteristics including nuclear DNA integrity was well characterized; however, the influence of sedentary work on sperm chromatin has not yet been documented. Therefore, our research was designed to examine the potential effects of sedentary work not only on conventional semen features but also on sperm nuclear DNA status. Materials and methods. The study was carried out on ejaculated sperm cells obtained from men who spent ≥ 50% of their time at work (≥ 17.5 h per week) in a sedentary position (n = 152) and from men who spent < 50% of their time at work in a sedentary position (n = 102). Standard semen characteristics were assessed according to the WHO 2010 recommendations, while sperm nuclear DNA fragmentation (SDF) was evaluated using the Halosperm test. Results. There were no significant differences in the standard semen parameters between the study groups. The groups differed only in SDF parameter. The men who spent at least 50% of their work time in a sedentary position had a higher proportion of SDF than the men who spent < 50% of their time at work in a sedentary position (median value 21.00% vs. 16.50%, respectively). The incidence of low SDF levels (related to 0–15% sperm cells with abnormal DNA dispersion) was significantly lower (27.63% vs. 45.10%), the percentage of men with high SDF levels (related to > 30%) was significantly higher (30.92% vs. 16.67%) in group of men who spent at least 50% of their work time in a sedentary positon. Furthermore, these men were more than twice as likely to have not a low SDF level (OR: 0.4648) and had more than twice the risk of having a high SDF level (OR: 2.2381) than the men in less sedentary occupations. Conclusions. Despite lack of association between sedentary work and conventional semen characteristics our study revealed detrimental effect of seated work on sperm nuclear DNA integrity. A sedentary job doubled the risk of high levels of sperm DNA damage. The pathomechanism could be related to testicular heat stress resulting in sperm chromatin remodelling failure during spermiogenesis. Therefore, it seems reasonable to simultaneously carry out routine seminological analyses and tests assessing sperm chromatin status while diagnosing male infertility. © Polish Society for Histochemistry and Cytochemistry Folia Histochem Cytobiol. 2019.
... In recent years, due to the increasing recognition of the negative effects of unrelieved heat and moisture on human health, microclimate changes at the user-seat interface have drawn more attention [1,23,24]. As changes in this category were originally considered to be an individual's physiological sensation (e.g., "I feel hot/wet"), they used to be subjectively evaluated by questionnaires [25]. ...
Being seated has increasingly pervaded both working and leisure lifestyles, with development of more comfortable seating surfaces dependent on feedback from subjective questionnaires and design aesthetics. As a consequence, research has become focused on how to objectively resolve factors that might underpin comfort and discomfort. This review summarizes objective methods of measuring the microenvironmental changes at the body–seat interface and examines the relationship between objective measurement and subjective sensation. From the perspective of physical parameters, pressure detection accounted for nearly two thirds (37/54) of the publications, followed by microclimatic information (temperature and relative humidity: 18/54): it is to be noted that one article included both microclimate and pressure measurements and was placed into both categories. In fact, accumulated temperature and relative humidity at the body–seat interface have similarly negative effects on prolonged sitting to that of unrelieved pressure. Another interesting finding was the correlation between objective measurement and subjective evaluation; however, the validity of this may be called into question because of the differences in experiment design between studies.
... To best mitigate these issues, a saddle chair with an overall height increase has been consistently proven to be both biomechanically better and preferred by users (Bendix, 1994;Bendix and Bridger, 2004;Corlett, 2009Corlett, , 1999Mandal, 1994bMandal, , 1994a1991, 1981Noro et al., 2012). Furthermore, the saddle configuration has been shown to create additional benefits, such as a consistent scrotal temperature due to more open trunk/thigh and hip angles compared to traditional seating (Koskelo et al., 2005). ...
Anthropometry is critical for product and workplace design. Highly prevalent, office work is associated with sedentarism and physical discomfort due to prolonged sitting. Dynamic seating (alternating across sitting, perching, and standing) has been suggested as an alternative to overcome those problems. The current study tested a large sample of anthropometric data for mismatch levels against national and international office furniture standards using dynamic seating as a framework with traditional and perching mismatch equations, applied to three recommended dynamic seating components. Dimensions present in the standards used did not match the majority of the sample. For sitting, seat width and depth individually presented the lowest levels of match, as well as under cumulative fit of all office furniture dimensions. However, these were alleviated when incorporating adjustability. Perching was shown to be generally impeded given commercially-available chair height options. Limitations in state-of-the-art perching equations are discussed, and two new models are proposed as design alternatives. Further research should focus on testing the criteria presented in this research through discomfort and objective measures.
... The influence of insulating clothing such as tight fitting underpants in contrast to boxer shorts has an impact on scrotal temperature, predominantly during physical activity, and is of minor influence during long periods of sitting (15). Compared to conventional chairs significantly lower scrotal temperatures could be observed with a so-called saddle chair, which allows a body position with open hip and knee angles resulting in sufficient perigenital air circulation (16). On the other hand, sitting on heated floors has been demonstrated as a potential genital heat stress factor among Asian men (17). ...
To evaluate the influence of a heated versus an unheated car seat on scrotal temperature under standardized experimental conditions.
Controlled clinical study.
Healthy volunteers in an academic research environment.
Thirty volunteers without a history of infertility and with a normal andrological examination.
Scrotal temperatures were measured every minute with a portable data recorder connected to two thermistor temperature sensors, which were attached on either side of the scrotum. All volunteers started the experiment at the same time of day wearing standardized cotton wool trousers and shirts fitting to body size. Each volunteer performed two periods of 90 minutes in a randomized manner on either the heated or unheated car seat.
At the end of the sitting periods scrotal temperatures were significantly higher using the heated car seat versus the unheated seat (left scrotal side: 0.5 degrees C; right scrotal side: 0.6 degrees C). Maximum values recorded during sitting alone were exceeded on the heated seat already after one-third of the exposure time.
The present study suggests that the frequent use of a heated car seat represents an additional scrotal, and consequently, testicular heat stress factor to that which is present by merely sitting for long periods.
... Moreover, an increase in the percentage of sperm with impaired motility was also observed (Brindley, 1982). The position of the body on the chair also affects perineum temperature; the intersection of legs generates more heat than the position with legs widened, revealing the perineum (Koskelo et al., 2005;Mieusset et al., 2007). However, there were no significant differences in scrotum temperature in case of lying down position; both the group of men with paraplegia and the group of healthy men achieved similar results (Brindley, 1982). ...
... 16,18 It is also possible that high BMI is associated with higher scrotal temperatures, and this can have adverse effects on spermatogenesis. 19 Laboratory studies in mice provide plausibility: disruption of insulin signaling causes both obesity and impaired spermatogenesis. 20 We did not have data on frequency of sexual intercourse. ...
Overweight and obese men have been reported to have lower sperm counts and hormonal changes, but data are lacking regarding effects on couple fertility.
We examined the relationship between male body mass index (BMI) and infertility in couples enrolled in the Agricultural Health Study in the United States. The analysis sample was limited to couples (wife <40 years old) with an attempt at pregnancy in the last 4 years based on pregnancy and fertility data provided by wives. Infertility was defined as not conceiving a pregnancy after at least 12 months of unprotected intercourse regardless of whether or not a pregnancy ultimately occurred. Self-reported weight and height were used to calculate BMI (kg/m). Adjusted odds ratios (aORs) for infertility associated with increases in male BMI were calculated with logistic regression.
Adjusting for potential confounders, a 3-unit increase in male BMI was associated with infertility (aOR = 1.12; 95% confidence interval = 1.01-1.25; n = 1329). There was a dose-response relationship, and the BMI effect was stronger when the data were limited to couples with the highest-quality infertility data. The association between BMI and infertility was similar for older and younger men, suggesting that erectile dysfunction in older men does not explain the association.
This report of lower fertility in overweight and obese men needs replication. If the findings are robust, programs to prevent obesity may improve men's reproductive health and save medical costs for infertility treatment.
... A 70 angle was considered large and not convenient to maintain for a long time in everyday life, but a smaller angle may not have such a beneficial effect. A significantly lower (up to 3 C) scrotal temperature was found in men sitting on the saddle chair with supported knee angle of 135 than in men sitting on commonly used chairs (45). Significantly higher (0.8 C-0.9 C) scrotal temperatures were documented after 15 minutes in a seated position with legs crossed than in a seated position with legs apart at an angle of 70 (16). ...
To evaluate methods of prevention of scrotal hyperthermia in laptop computer (LC) users.
Experimental study.
University hospital.
Twenty-nine healthy male volunteers.
Right and left scrotal temperature and LC and lap pad temperatures were recorded during three separate 60-minute sessions using a working LC in a laptop position: session 1, sitting with closely approximated legs; session 2, sitting with closely approximated legs with a lap pad below the working LC; and session 3, sitting with legs apart at a 70°angle with a lap pad below the working LC.
Scrotal temperature elevation.
Scrotal temperature increased significantly regardless of leg position or use of a lap pad. However, it was significantly lower in session 3 (1.41 °C ± 0.66 °C on the left and 1.47 °C ± 0.62 °C on the right) than in session 2 (2.18 °C ± 0.69 °C and 2.06 °C ± 0.72 °C) or session 1 (2.31 °C ± 0.96 °C and 2.56 °C ± 0.91 °C). A scrotal temperature elevation of 1 °C was reached at 11 minutes in session 1, 14 minutes in session 2, and 28 minutes in session 3.
Sitting position with closely approximated legs is the major cause of scrotal hyperthermia. Scrotal shielding with a lap pad does not protect from scrotal temperature elevation. Prevention of scrotal hyperthermia in LC users presently is not feasible. However, scrotal hyperthermia may be reduced by a modified sitting position (legs apart) and significantly shorter use of LC.
... Possible explanations include altered concentrations of circulating sex steroids in obese men (increased concentrations of oestrogens and decreased concentrations of total testosterone and FSH) (Fejes et al., 2006;Glass et al., 1977;Schneider et al., 1979;Zumoff et al., 1990;Glass et al., 1977), (Jensen et al., 2004;Pauli et al., 2008;Strain et al., 1982). Increased scrotal temperature as a result of increased suprapubic, thigh or scrotal fat (El-Sibai and Fouad, 1997;Koskelo et al., 2005;Shafik and Olfat, 1981) is a second possible mechanism of decreasing semen quality in these subjects. ...
Obesity is becoming a serious problem, especially in industrialized societies. This study was designed to explore the association between body mass index (BMI) and semen quality. Semen analysis and demographic data were collected from male partners of couples undergoing fertility investigations in a referral fertility centre. Men were classified into groups according to their BMI (A, <18.5; B, 18.5-24.99; C, 25-29.99; D, ≥30 kg/m(2)). Data from 2035 men were analysed using logistic regression. There were 18, 839, 909 and 269 men in groups A, B, C and D, respectively. Taking group B as the reference, adjusted odds ratios (95% CI) for groups A, C and D for semen volume <2 ml were 1.57 (0.49-5.01), 1.06 (0.82-1.38) and 1.69 (1.20-2.38), respectively; for sperm morphology <15%, 1.44 (0.45-4.61), 1.07 (0.86-1.33) and 1.50 (1.06-2.09); for sperm concentration <20 million/ml, 0.46 (0.10-2.07), 1.03 (0.82-1.31) and 1.00 (0.72-1.41); and for motility <50%, 2.62 (0.73-9.45), 0.96 (0.78-1.18) and 0.75 (0.56-1.01). In conclusion, obese men are more likely to have lower semen volume and fewer morphologically normal spermatozoa than men with normal BMI.
... Modern people like deep cushioned and comfortable chairs, but the thickness of a cushion and chair style contribute to increasing testicular temperature [86]. Hjollund et al. [87] found that a sedentary work position on a chair was a strong determinant of scrotal temperature (<1 h sedentary: 33.1 C, and >6 h sedentary: 34.7 C). ...
The human body responds psychologically and physiologically to the thermal environment to which it is exposed. Fanger's PMV model has been adopted for the design of built environments and building maintenance from the end of the 1960s. The sperm quality of humans has been decreasing since the 1970s. The thermal environment is one of the most important factors of the Sick Building Syndrome (SBS). It is well known that spermatogenesis is very sensitive to heat exposure. Mild thermal exposure increases tissue microcirculation and consequently produces an appropriate supply of nutrients and oxygen to tissue cells; thus, it can modulate the proliferation of Sertoli cells in which the spermatogonia stem cells develop into adult spermatozoa. Excessive exposure to heat is harmful to spermatogenesis, and excessive testicular cooling can cause the cessation of spermatogenesis.The thermal regulatory system in humans differs individually, according to the characteristics of thermal adaptation for each person. Even in the same thermal environment, each occupant responds differently. A personal air-conditioning system or partial heating or cooling system is the most interesting topic for future research to increase male health and to decrease energy consumption.
... Wearing tight underwear or using a laptop on the knees (heat produced by battery) also may increase scrotal temperature. 33 ...
Fertility literacy is defined as the degree to which people understand fertility information. The reproductive system reflects overall health in men and women. Alterations are associated with chronic disease risk and pregnancy outcome. At every patient visit, whether for acute or chronic care, consideration should be given to any woman who, although not pregnant, may become pregnant. Addressing male fertility is also important as women do not bear responsibility for healthy pregnancy alone. This article provides the primary care nurse practitioner with a concise guide of current information and recommendations for guiding men in the primary care setting.
... The position of one's legs and the type of chair used also influence scrotal temperatures. For example, sitting cross-legged on a typical cushioned office chair is likely to generate more scrotal heat compared with sitting on a saddle seat with wide-angled hips and knees, as the latter position promotes perigenital ventilation (Koskelo et al., 2005;Mieusset et al., 2007). Heat from the seated surface, as from a heated car seat or a heated floor, further adds to scrotal temperatures that are already elevated from being in a seated position (Jung et al., 2008a;Song and Seo, 2006). ...
The process of spermatogenesis is temperature-dependent and occurs optimally at temperatures slightly lower than that of the body. Adequate thermoregulation is imperative to maintain testicular temperatures at levels lower than that of the body core. Raised testicular temperature has a detrimental effect on mammalian spermatogenesis and the resultant spermatozoa. Therefore, thermoregulatory failure leading to heat stress can compromise sperm quality and increase the risk of infertility. In this paper, several different types of external and internal factors that may contribute towards testicular heat stress are reviewed. The effects of heat stress on the process of spermatogenesis, the resultant epididymal spermatozoa and on germ cells, and the consequent changes in the testis are elaborated upon. We also discuss the molecular response of germ cells to heat exposure and the possible mechanisms involved in heat-induced germ cell damage, including apoptosis, DNA damage and autophagy. Further, the intrinsic and extrinsic pathways that are involved in the intricate mechanism of germ cell apoptosis are explained. Ultimately, these complex mechanisms of apoptosis lead to germ cell death.
The prevalence of overweight and obesity is increasing worldwide. There is an established association between female obesity and infertility but a similar link is yet to be proven in men. Herein we review publications, identified via keyword electronic database searches (1980—2008), which considered the influence of adiposity on male reproductive potential. It would appear that obesity has a detrimental effect on semen quality and that there are several potential mechanisms underlying this phenomenon.Br J Diabetes Vasc Dis 2009;9: 7—12
Testicular temperature highly correlates with scrotal temperature. It has been postulated that cycling is associated with increased scrotal temperatures with time and consecutively with impaired semen quality. The aim of this study was to evaluate the influence of moderate cycling on scrotal temperature during highly standardized conditions in an experimental lab. A total of 25 volunteers without a history of infertility and normal andrological examination were included for scrotal temperature evaluation. Scrotal temperatures were measured every minute with a portable data recorder connected with two thermistor temperature sensors, which were attached on either side of the scrotum. A further thermistor sensor was attached on the central surface of the bicycle saddle. Ambient temperature in the study room was adjusted to 22°C throughout the whole experiment. All volunteers started the experiment at the same daytime. Clothing of the volunteers consisted of standardized cotton wool trousers and shirts fitting to body size. After acclimatization to the study room in a sitting posture, each volunteer cycled on an exercise cycle for 60 min with a power of 25 Watt representing a speed of 25.45 km/ h respectively. The saddle surface temperature reached in the median 35.59°C after 60 min cycling. Median values of scrotal temperatures increased from 35.75°C at the beginning to 35.82°C after 60 min for the left side and from 35.50 to 35.59°C for the right side. No correlation between cycling duration and scrotal temperatures could be found using multivariate anova for repeated measurements. However, scrotal temperatures during cycling were significantly lower (p < 0.001) compared with the last 10 min in sitting posture before starting cycling with a difference of 1.31°C for the left and 1.46°for the right side. The present study suggests that moderate cycling under standardized conditions with a power of 25 Watt is not a major genital heat stress factor. Journal compilation
A comprehensive literature search in multiple databases yielded 2926 hits for the search terms thermometry and thermography. Therefore, this literature survey is based only on publications listed in the databases Embase and Medline between 1.1.2005 and 31.12.2005 and matching with one of the following 8 keywords: “thermograpy”, “thermology“, “ “thermal imaging”, “infrared imaging”, thermometry”, “temperature measurement”, “skin temperature” and “core temperature”. After restricting the number of hits by combining the search terms with the key word “human, 735 references were obtained. Thermal imaging was the main subject of 169 papers, all other publications were related to temperature measurements in humans. This literature survey has demonstrated a continuously high interest in both temperature related physiology and temperature related treatment mainly hypothermia for patients in a critical state of health.
Tactile interaction between humans and elements in the built environment, such as furniture, is often under-appreciated. The aim of this study was to objectively evaluate thermal properties of ten tabletop materials as well as user perceptions of those materials after use. Sixteen participants tested ten materials in a randomised order. Infrared thermography was used to determine tabletop temperature distribution and change. Materials with lower thermal effusivity (wood-based materials) in general reached higher surface temperature differences after 15 min of contact and were rated as more pleasant to touch, more suitable for writing, and more liked for everyday use. Participants' sex and forearm mass had no effect on the temperature after contact. Participants gave the highest ratings to the appearance of oak-based materials. Surface treatment affected subjective evaluation of the materials. The tabletop made of lacquered solid wood had the most favourable thermal and user-rated characteristics.
Objective:
To evaluate awareness amongst general population attending Civil Hospital Karachi regarding risk factors associated with infertility.
Methods:
A descriptive study was conducted on subjects who were attendants to the patients admitted in Civil Hospital Karachi or had appointment in outpatient department. They were interviewed one-on-one after their verbal consent, through separate questionnaires for each gender, from September 2012 to January 2013. Minimal age of the respondents included was 18 years. Data was entered and analyzed in SPSS (version 20.0).
Results:
A total of 289 attendants were interviewed, 150 were females, with mean age 38.1 +/- 11.3 years, remaining 139 were males having a mean age of 32.5 +/- 9.9 years. Correct knowledge about the risk factors causing infertility was found to be limited among people. Only 159 (66.9%) and 142 (49%) of the total respondents recognized obesity and diabetes as a threat. Just 54 (36%) and 72 (48%) of females were able to appreciate hirsutism and menorrhagia respectively as cause. Sixty (43%) and 67 (48%) of males considered mumps and smoking respectively as culprits. In contrast to previous researches, men received greater votes for being a probable victim of infertility (55%; 159 of the total respondents).
Conclusion:
Inadequacy of knowledge about infertility was clearly demonstrated through this study. This lack of knowledge explains why such a strong stigma is attached to infertility in the society.
Concern about the decline in human semen parameters has grown in recent years, due in part to the increase in infertility consultations. Semen quality may be influenced by environmental or lifestyle factors such as the practice of physical activity but the relation between semen quality and physically active lifestyle is not clearly established. Nevertheless, it has been proposed that physical activity might have positive effects on semen quality as well as it has various health benefits. To possibly include the improvement of semen quality on the reasons to stimulate the physically active lifestyle in people, it's necessary to increase the knowledge about the influence of diverse aspects involved on the practice of physical activity on the sperm parameters. The purpose of this literature review is to compile the main aspects related to the effect of lifestyle, particularly physical activity and sedentarism on semen quality.
The testis is a temperature-sensitive organ that needs to be maintained 2–7°C below core body temperature to ensure the production of normal sperm. Failure to maintain testicular temperature in mammals impairs spermatogenesis and leads to low sperm counts, poor sperm motility and abnormal sperm morphology in the ejaculate. This review discusses the recent knowledge on the response of testicular somatic cells to heat stress and, specifically, regarding the relevant contributions of heat, germ cell depletion and inflammatory reactions on the functions of Sertoli and Leydig cells. It also outlines mechanisms of testicular thermoregulation, as well as the thermogenic factors that impact testicular function.
It is understood that posture and support affect discomfort and consequently have received widespread attention from researchers. Another factor that could contribute to comfort is the thermal influence due to interaction between the human and the seating surface for which literature is limited. The primary focus of this research was to identify a user's self-selected thermal comfort on a traditional foam-based seat pan while performing a typing/mousing/reading task. A psychophysical approach was applied to evaluate the thermal influence of a task chair with the seat pan temperature as the objective variable. The method of adjustments protocol used two testing sessions with different initial settings. Results of the preliminary study with 10 female participants between 30 and 45 years indicated that the psychophysical methodology is applicable for the purpose. Results also indicate that users' self-selected comfort was achieved when the average temperature of the seat-pan interface was lower than the participant's oral body temperature.
Relevance to industry
Properties of seat pan materials should be considered by chair designers, which could help alleviate the thermal discomfort experienced by chair users.
Abstract
Objective: To evaluate awareness amongst general population attending Civil Hospital Karachi regarding risk
factors associated with infertility.
Methods: A descriptive study was conducted on subjects who were attendants to the patients admitted in Civil
Hospital Karachi or had appointment in outpatient department. They were interviewed one-on-one after their
verbal consent, through separate questionnaires for each gender, from September 2012 to January 2013. Minimal
age of the respondents included was 18 years. Data was entered and analyzed in SPSS (version 20.0).
Results: A total of 289 attendants were interviewed, 150 were females, with mean age 38.1±11.3 years, remaining
139 were males having a mean age of 32.5±9.9 years. Correct knowledge about the risk factors causing infertility was
found to be limited among people. Only 159 (66.9%) and 142 (49%) of the total respondents recognized obesity and
diabetes as a threat. Just 54 (36%) and 72(48%) of females were able to appreciate hirsutism and menorrhagia
respectively as cause. Sixty (43%) and 67 (48%) of males considered mumps and smoking respectively as culprits. In
contrast to previous researches, men received greater votes for being a probable victim of infertility (55%; 159 of the
total respondents).
Conclusion: Inadequacy of knowledge about infertility was clearly demonstrated through this study. This lack of
knowledge explains why such a strong stigma is attached to infertility in the society.
Keywords: Awareness, Risk factors, Infertility.
There is a need to develop a greater understanding of temperature at the skin–seat interface during prolonged seating from the perspectives of both industrial design (comfort/discomfort) and medical care (skin ulcer formation). Here we test the concept of predicting temperature at the seat surface and skin interface during prolonged sitting (such as required from wheelchair users). As caregivers are usually busy, such a method would give them warning ahead of a problem. This paper describes a data-driven model capable of predicting thermal changes and thus having the potential to provide an early warning (15- to 25-min ahead prediction) of an impending temperature that may increase the risk for potential skin damages for those subject to enforced sitting and who have little or no sensory feedback from this area.
This study has modeled numerous confounding parameters of seminal quality for the purpose of digging out the hidden relationship between these seminal parameters using Bayesian Belief Network (BBN). The data source for this study was retrieved from UCI machine learning repository. Etiological patterns were derived out of complex relationship of nine related attributes. We have shown that as compared to conventional statistical measures, BBN is quite useful in analysis of seminal quality as well as classifying an unknown instance. The outcome is composed of a predictive probabilistic model which can classify any new instance whether the seminal quality is altered or not. The observed accuracy of the model is highest (91%) whereas the previous highest accuracy was reported to be 86% only.
With technological advancements, we have evolved into a species that is surrounded by a number of potential hazards that may endanger our own survival. One of the important aspects of the effect of modern lifestyle is increased incidence of infertility. Renewal being the most important requirement for a species, fertility loss can have radical consequences. Since fertility does not need to be earned, it is taken to be immune to changes in lifestyle and surroundings. While a number of poor lifestyle practices are adopted, we fall prey to other hazards inadvertently. We recognized the effect of lifestyle on fertility a little late, but fortunately it is neither too late nor too difficult to confront the lifestyle factors that may take a heavy toll on fertility. In this chapter, I have provided the most comprehensive review of a number of lifestyle factors that matter to fertility and simple ways to overcome their potential perils. Following a great lifestyle ardently may be a difficult task, but can have great therapeutic rewards.
Introduction: Musculoskeletal symptoms related to using traditional computer workstations are common. To improve ergonomics of workstations quantitative methods for measuring muscle stress and strain are needed. We hypothesize that infrared thermography (IRT) is suited for this purpose.
Methods: This hypothesis was evaluated by estimating muscle activity in upright and traditional working postures with IRT and surface electromyography (sEMG). IRT and sEMG measurements were conducted in 14 female participants with both working postures. First, measurements with the traditional posture were performed. Later, participants had one month to adjust to the upright working posture before repeating the measurements. IRT images were acquired before and after a full working day with sEMG recordings being conducted throughout the measurement days. Participants evaluated their neck pain severity using neck disability index (NDI) questionnaires before the first and after the second measurement day.
Results: Spatial variation in upper back temperature was higher (p=0.008) when working in traditional posture and that the upright working posture reduced (p<0.05) the upper back muscle activity. NDI value was significantly lower (p=0.003) after working in upright posture.
Conclusion: IRT was found suitable for evaluating muscle activity and upright working posture to reduce NDI value and muscle activity in upper back.
Background:
The quality of semen depends upon several factors such as environment, life style, physical activity, age, and occupation. The aim of this study was to analyze and compare the conventional and functional semen parameters in men practicing vigorous physical activity to those of sedentary men.
Materials and methods:
In this descriptive cross-sectional study, semen samples of 17 physically active men and 15 sedentary men were collected for analysis. Semen analysis was performed according to the World Health Organization (WHO) guidelines, while functional parameters were evaluated by flow cytometry.
Results:
Results showed that several semen parameters (semen volume, viability, progressive motility, total motility, normal morphology, and moribund cells) were superior in the physically active group in comparison with the sedentary group. Semen parameters such as viability, progressive motility and total motility, as well as the percentage of moribund spermatozoa were significantly different between both groups. However, sperm DNA damage, lipid peroxidation and mitochondrial potential were not significantly different among the groups.
Conclusion:
Nevertheless, the physical activity shows better semen parameters than sedentary group. Taken together, our results demonstrate that regular physical activity has beneficial impact in sperm fertility parameters and such a life style can enhance the fertility status of men.
Zusammenfassung
Sowohl die Klimaerwärmung als auch die Unfruchtbarkeit von Männern – besonders in der westlichen Welt – sind hochaktuelle Themen. Es drängt sich die Frage auf, ob zwischen diesen beiden Themen ein kausaler Zusammenhang besteht. Viele endo- wie auch exogene Faktoren haben einen negativen Einfluss auf die Fruchtbarkeit von Männern. Haupteinflussfaktoren hierbei stellen die Fettleibigkeit und die damit verbundenen Komorbiditäten wie Diabetes mellitus und Atherosklerose dar. Zwar ist die Spermatogenese temperaturabhängig, aber ein eindeutiger Zusammenhang zwischen Klimaerwärmung und einem erniedrigten Testosteronspiegel ist bis jetzt nicht erkennbar, wobei jedoch zur genaueren Untersuchung weitere Studien erforderlich sind.
The concept that an elevation of testicular temperature results in impairment of spermatogenesis is widely accepted. Here, current knowledge concerning genital heat stress and its consequences in men is reviewed. Duration of sitting during work positively correlates with daytime scrotal temperatures and daytime scrotal temperature negatively correlates with semen quality. However, the assumed negative correlation between duration of sitting and semen quality could not be shown in the available studies. Fertility parameters of professional drivers with long periods of sitting in vehicles were impaired; however, for predominantly affected drivers of vans, trucks or industrial heavy machinery potential confounders have to be considered. Wearing tight fitting compared with loose-fitting underwear is associated with significantly higher scrotal temperatures. However, available observations suggesting a link between tight-fitting underwear or trousers and impaired semen quality are not convincing. Studies addressing professional exposure to high temperatures delivered conflicting results concerning fertility parameters. The postulated negative impact of sauna visits on semen quality is not sufficiently underlined by the available studies. Oligozoospermic men with a varicocele have significantly higher scrotal temperatures than normozoospermic men, and according to several studies varicocelectomy normalises scrotal temperatures. A further link has been reported between fever and deteriorated semen quality. Contraception via genital heat stress has been demonstrated using hot sitting baths or insulating suspensors. However, down-regulation of spermatogenesis is inconsistent and unsafe. On the other hand, scrotal and consecutively testicular cooling is able to improve semen quality.
Recent reports have suggested that the incidence of genitourinary abnormalities in human males has increased during the past 50 years, including congenital abnormalities such as cryptorchidism and hypospadia, which seem to be occurring more commonly. Also, the incidence of testicular cancer has increased 3- to 4-fold since the 1940s. This increase seems to be worldwide including countries with a very high frequency of testicular neoplasia as well as those in which this cancer is rather uncommon. It has also been postulated that semen quality has been decreasing for the last half century. A recent study showed that the average sperm density has decreased significantly from 113 million/mL in 1940 to 66 million/mL in 1990. The mean seminal volume has also declined, indicating that the decrease in the total sperm count is even more pronounced than the fall in sperm density would indicate. The remarkable increase in frequency of testicular abnormalities over a relatively short period of time may be due to environmental rather than genetic factors. There is an epidemiological link between the occurrence of different testicular abnormalities. Therefore, common prenatally acting etiological factors with adverse effects on the fetal male gonad might be suspected. However, postnatal influences may also have a deleterious effect on male fertility. From the reproductive point of view, an increased impact on the human male gonad is of concern.
Several recent studies have reported a gradual decline in sperm production in men. Endocrine disrupters as well as lifestyle
have been suggested as risk factors. One lifestyle factor that may affect human fertility is driving a vehicle for a prolonged
period. Several authors have suggested that driving position may increase the scrotal temperature. In order to validate this
hypothesis we conducted continuous monitoring of scrotal temperature in real conditions, i.e. in men driving a car for a prolonged
period. Nine volunteer men were asked to walk outside for 40 min and then to drive a car for 160 min. Scrotal temperatures
were measured from thermocouples and values recorded every 2 min on a portable data recorder. Scrotal temperature increased
significantly (P < 0.0001) in driving posture after 2 h of driving, reaching a value 1.7–2.2°C higher than that recorded while walking. This
link between driving position and increased scrotal temperature indicates a potential exposure of male reproductive function
to lifestyle factors.
Two new techniques for measuring deep scrotal temperature are described. Paraplegic men in wheelchairs have deep scrotal temperatures averaging about 0.9 degrees C higher than normal sitting men, and those whose scrotal temperatures are very high usually lack motile spermatozoa. In the author, deep scrotal temperatures at constant air temperature are 0.5 degrees C lower wearing boxer shorts than wearing Y-fronts, and 1.2 degrees C lower wearing scrotal slit underpants than wearing boxer shorts; they are 1.6 degrees C lower sitting with thighs apart than sitting with thighs together, and 0.5 degrees C lower running than sitting with thighs apart. From such observations, means of lowering paraplegic deep scrotal temperatures can be designed.
Infertility currently affects at least one man in 20, but we are unable to assess whether it is becoming more prevalent because we have extremely poor past records. Male reproduction has been given little attention scientifically and in medical practice. However, our recent meta-analysis in the BMJ of 61 papers on semen quality, which clearly pointed to a decrease over the past 50 years,1 has been repeatedly quoted in the BMJ,2 3 4 Science,5 and the popular media.
We have already responded to the various technical criticisms, several of which concerned the known limitations of meta-analysis.\*RF6-8\* Though the data for 1970-90 were compatible with a decrease as well as with no change or an increase in semen quality, the cautious general conclusion is that a real decline in semen quality did occur over the full period 1940-90. Three recent reports have found that semen quality has declined among candidates …
To determine whether geographic variations in sperm counts might bias conclusions drawn from studies of semen quality.
Reanalysis of published data from a meta-analysis of 61 studies from 1938 to 1990 that concluded a worldwide decline in semen quality over the last 50 years.
Influence of geographic location on sperm counts.
Of 61 studies in the meta-analysis, only 20 included > or = 100 men. These 20 studies collectively comprised 91% of the total men studied. We focused our reanalysis on these 20 studies. Of the studies before 1970, all were from the United States and 80% were from New York. These studies represented locations with the highest sperm counts. In contrast, after 1970, 80% of the studies were from locations not represented earlier, including five studies from third world countries, where sperm counts were low.
Sperm counts vary dramatically among different geographic locations.
Introduction of new technologies involving many chemicals does not remain free from the effect on the human health. Occupational acute poisoning is rare now-a-days, but we often face many problems arising out of the late sequel to exposures, such as mutations, neoplasms or reproduction disorders. Numerous research institutes of occupational medicine are involved in the evaluation of the effect of environmental factors on the workers' health. Many recent publications emphasise that the quality of the human semen is gradually decreasing which is manifested by the lower number of spermatozoons (1 cm3) semen, a higher proportion of morphologically impaired spermatozoons and a higher per cent of motile spermatozoons. The quality of the semen is affected not only by the hazards present in the general environment, but also by the factors occurring in the work environment. Occupational exposure induces sometimes infertility of couples but more often impairs the reproduction, and this is one of important issues which be addressed by occupational medicine.
To determine whether application of polyester-lined athletic supports to bring the testes closer to the abdomen increases scrotal temperature and decreases sperm production.
Prospective clinical study.
University academic medical center.
Twenty-one healthy male volunteers.
The study consisted of a pretreatment period of 6 weeks, a treatment phase of 52 weeks, and a recovery phase until return to normal sperm production. During the treatment phase, the men wore polyester-lined athletic supports (single layer, double layer, or double layer impregnated with aluminum) throughout the day.
Semen parameters and sperm function tests.
In all three groups of subjects, scrotal temperature was consistently increased by 0.8 to 1 degree C while the subjects were wearing the athletic supports. Mean sperm concentration; sperm motility, morphology, and viability; sperm hyperactivation; and ability of spermatozoa to penetrate zone-free hamster oocytes were not affected by the increase in scrotal temperature.
The increase in scrotal temperature induced by polyester-lined athletic supports was insufficient to cause significant suppression of spermatogenesis or alteration of sperm function.
After the meta-analysis by Carlsen et al. (1992) showing a decline in human sperm count over the last 50 years, several studies have been made on the sperm characteristics of more or less homogeneous groups of men who were collecting semen in the same center for 10-20 years. A significant decline in sperm count was reported in some studies but not in others. The debate on declining sperm counts is not closed and these studies raised the following important questions: could the differences in results be the reflect of variation in techniques or blas in methodologies? If these phenomena are real, why a deterioration of semen quality in some places and not in others with so important geographical differences of sperm production? What are the possible consequences on human fertility and what are the causes? Unfortunately, there is presently no answer. The danish study provoked extensive discussion on the many possible sources of bias while there was less controversy concerning the studies carried out in a single center despite the extent of limitations of several of them. Recent publications indicated concomitant and increasing alterations of the development and/or function of the male genital tract, various observations in the wildlife and several experimental studies suggesting the possible deleterious role of numerous chemical compounds present in our environment. Therefore, prospective epidemiological studies and fundamental researchs are urgently needed.
Semen analysis is part of the routine assessment of infertile couples. WHO defines a sperm concentration above 20x10(6) per mL seminal fluid as normal. We studied the association between semen quality and the probability of conception in a single menstrual cycle in Danish couples with no previous reproductive experience.
In 1992-94, we invited 52,255 trades-union members aged 20-35 years, who lived with a partner and had no children to take part in the study; 430 couples agreed. The couples discontinued use of contraception, and were followed up for six menstrual cycles or until a pregnancy was verified within this period. Each man was asked to provide a semen sample at enrolment (which was analysed without freezing). Women kept a daily record of vaginal bleeding and sexual activity. The association between semen quality and likelihood of pregnancy was assessed by logistic regression, adjusted for sexual activity and female factors associated with low fertility.
There were 256 (59.5%) pregnancies among the 430 couples: 165 (65.0%) among those with a sperm concentration of 40x10(6)/mL or more and 84 (51.2%) among those with lower sperm concentrations. The probability of conception increased with increasing sperm concentration up to 40x10(6)/mL, but any higher sperm density was not associated with additional likelihood of pregnancy. The proportion of sperm with normal morphology was strongly related to likelihood of pregnancy independently of sperm concentration. Semen volume and motility were of limited value in pregnancy prediction.
Our study suggests that the current WHO guidelines for normal semen quality should be used with caution. Some men with sperm counts above the lower limit of the normal range defined by WHO may in fact be subfertile.
Our understanding of the importance of environmental and lifestyle factors on sperm count and fertility is constrained by the extreme variation in sperm count between men and between ejaculates. The factors responsible for this variation provide a key to understanding what factors actually affect the sperm count. The relative importance of the various factors and the pathways via which they affect sperm count are discussed. The most important are Sertoli cell number, ejaculatory frequency, season, factors affecting scrotal heating (e.g. the time spent seated), a past history of reproductive tract disorders and ageing. The possible role of other environmental factors commonly supposed to affect sperm count (exposure to pesticides or endocrine disruptors) is discussed, although the evidence for a major influence of such factors is lacking. It is suggested that lifestyle changes, especially in the time spent seated, will exert an adverse effect on sperm production in a progressively larger group of men over the next decade.
A questionnaire assessing factors that might cause an increase in scrotal temperature was completed by patients with reproducible oligoasthenoteratozoospermia of idiopathic nature or caused by varicocele. Evaluation by means of a grading scale revealed increased scrotal heat stress in oligoasthenoteratozoospermic patients compared with normozoospermic men (P < 0.01). In addition, long-term determination of 24 h scrotal temperature profiles showed that compared with semen donors, oligoasthenoteratozoospermic patients frequently had scrotal temperatures above 35.5 degrees C despite the same environmental temperatures (P < 0.05). In 88% of cases, maximum scrotal temperatures were measured during rest or sleep phases, whereas minimum values were recorded during physical activity or frequent change of position. Nocturnal scrotal cooling by means of an air stream resulted in a decrease in scrotal temperature of approximately 1 degrees C. Furthermore, a highly significant increase in sperm concentration (P < 0.0001) and total sperm output (P < 0.0001) was achieved after nocturnal scrotal cooling for 12 weeks together with a moderate decrease in factors leading to genital heat stress. A significant improvement in sperm motility (P < 0.05) and sperm morphology (P < 0.05) was also observed, but this improvement was markedly less pronounced than the changes in sperm concentration. This study shows the importance of genital heat stress as a cofactor in fertility impairment in men and indicates nocturnal scrotal cooling as a therapeutic option.
A high scrotal temperature is a common finding in infertile patients and experimental studies indicate that specific types of heat exposure reduce semen quality. More and more men have a sedentary work position, which increases scrotal temperature. Semen and blood samples from 99 healthy men were analysed in relation to scrotal skin temperature obtained by a 24-h continuous monitoring protocol. Information on sedentary position at work and during spare time was collected by questionnaires. A negative correlation was found between high scrotal temperature and sperm output. Sperm concentration decreased 40% per 1 degrees C increment of median daytime scrotal temperature (95% CI: 8-71%). Similar results were found for total sperm count, FSH, and inhibin B. Motility, morphology, pH, and testosterone were not significantly associated with temperature. Only weak and inconsistent associations were found between sedentary position and semen quality. We conclude that scrotal temperature and semen quality are closely associated. Sedentary work position encountered in ordinary jobs, although a strong determinant of scrotal temperature, does not seem to have any effect on semen quality.
Normal sperm production depends on a testicular temperature below body temperature, but the thermogenic effects of daily life activities are not well known. We described the association between scrotal temperature and daily activities in 101 males using a non-invasive method for measuring scrotal temperature. A thermistor was attached to the underwear and the temperature of the scrotal skin was logged by a portable device every 5 min for 24h. Participants reported sedentary position and activities at work and during spare time in a questionnaire. Scrotal temperature was strongly correlated with sedentary work position with a dose-effect association (<1 h sedentary: 33.1 degrees C, >6 h sedentary: 34.7 degrees C, median values). The variation in sedentary work accounted for 31.5% of the variation in median temperature during the entire 24h. Sedentary position during spare time did not correlate with scrotal temperature. Median temperature at night was 1.2 degrees C higher than during the daytime. No effect was found for size or reported tightness of the underwear. In a model experiment, the deviance between testicular and scrotal temperature was estimated as maximally 0.1-0.6 degrees C, depending on the type of activity. Measuring scrotal temperature provides a valid estimate of testicular temperature and is feasible in large cohorts. We conclude that work position is an important determinant of testicular temperature.
Testicular temperature correlates highly with scrotal temperature. The aim of this study was to evaluate the influence of the type of undertrousers on scrotal temperature during standardized periods of sitting and walking.
Fifty volunteers without a history of infertility and normal andrological examination were included for scrotal temperature evaluation. Temperatures were measured every minute with a portable data recorder connected with two thermistor temperature sensors, which were attached on either side of the scrotum. Ambient temperature in the study room was adjusted to 20 degrees C throughout the whole experiment. All volunteers started the experiment at the same time of day. Clothing of the volunteers consisted of standardized cotton wool trousers and shirts fitting to body size. Each volunteer performed six periods of 45 min, either walking on a treadmill (3.0 km/h) or sitting, and wearing in a standardized and randomized manner either tight, loose fitting or no undertrousers respectively.
The following interactions were demonstrated by means of multivariate analysis of variance for repeated measurements: scrotal temperatures were significantly higher for tight versus loose fitting versus absent undertrousers. Furthermore, significantly lower scrotal temperatures were identified for walking versus sitting as well as for the right versus the left scrotal side.
The present study suggests that wearing tight fitting undertrousers is associated with higher scrotal and consequently testicular temperatures than wearing loose fitting undertrousers or none.
Evidence for increasing incidence of abnormalities of the human testis: a review
- Giwercman
Effect of increased scrotal temperature on sperm production in normal men
- Wang