Changes

*Mortality rate during heat waves increases with age.<ref> Oechsli et al, 1970 </ref> <ref> Buechley et al, 1972 </ref> The elderly seem to suffer from impaired physiological responses and often are unable to increase their cardiac output sufficiently during extremely hot weather.<ref> Sprung C.L., 1979  </ref>

*Mortality rate during heat waves increases with age.<ref> Oechsli et al, 1970 </ref> <ref> Buechley et al, 1972 </ref> The elderly seem to suffer from impaired physiological responses and often are unable to increase their cardiac output sufficiently during extremely hot weather.<ref> Sprung C.L., 1979  </ref>

*It was noted that men who had taken bath in 15oC water for one-half hour over nine consecutive days before a trip to the Arctic showed less signs of cold-induced stress than non-treated men. It indicates that adaptation to cold temperatures can occur through repeated exposures. <ref> Radomski and Boutelier, 1982 </ref>

*It was noted that men who had taken bath in 15oC water for one-half hour over nine consecutive days before a trip to the Arctic showed less signs of cold-induced stress than non-treated men. It indicates that adaptation to cold temperatures can occur through repeated exposures. <ref> Radomski and Boutelier, 1982 </ref>

*To a great extent, the seasonal changes in the immune system are controlled by changes in the levels of various hormones, particularly melatonin. Serum levels of melatonin were found to be highest in the winter months in both normal individuals and SLE patients.<ref> Nelson et al., 2000 </ref> There is natural increase in ''bala'' (strength/immunity) of individuals during winter i.e. ''hemanta'' and ''shishira ritu''.

*To a great extent, the seasonal changes in the immune system are controlled by changes in the levels of various hormones, particularly melatonin. Serum levels of melatonin were found to be highest in the winter months in both normal individuals and SLE patients.<ref> Nelson et al., 2000 </ref> There is natural increase in ''bala'' (strength/immunity) of individuals during winter i.e. [[hemanta]] and [[shishira]] [[ritu]].

*Striking seasonal variations have been demonstrated in the plasma and saliva levels of the glucocorticoid, cortisol, which promotes carbohydrate metabolism. The lowest levels of cortisol were found in healthy individuals during spring and summer, while the highest levels were found during autumn and winter seasons.<ref>  Walker et al, 1997 </ref>

*Striking seasonal variations have been demonstrated in the plasma and saliva levels of the glucocorticoid, cortisol, which promotes carbohydrate metabolism. The lowest levels of cortisol were found in healthy individuals during spring and summer, while the highest levels were found during autumn and winter seasons.<ref>  Walker et al, 1997 </ref>

*''Agni'' (digestive power) of individuals is strong during winter i.e. ''hemanta'' and ''shishira ritu'', and weakest during ''grishma'' and ''varsha ritu.''

*''Agni'' (digestive power) of individuals is strong during winter i.e. [[hemanta]] and [[shishira]] [[ritu]], and weakest during [[grishma]] and [[varsha]] [[ritu]].

*Rheumatic diseases vary in severity by season. The incidence of acute gouty attacks (an inflammatory arthritis) is highest in the spring season.<ref> Schlesinger N et al., 1998 </ref> Schlesinger N.et al. (2009) explained in his paper “Seasonal Variation of Rheumatic Diseases” that seasonal variation has been shown in a number of rheumatic diseases.<ref> Schlesinger N et al, 2009 </ref>

*Rheumatic diseases vary in severity by season. The incidence of acute gouty attacks (an inflammatory arthritis) is highest in the spring season.<ref> Schlesinger N et al., 1998 </ref> Schlesinger N.et al. (2009) explained in his paper “Seasonal Variation of Rheumatic Diseases” that seasonal variation has been shown in a number of rheumatic diseases.<ref> Schlesinger N et al, 2009 </ref>

*Coronary artery disease shows a winter peak and summer trough in incidence and mortality.<ref> Sher L., 2001 </ref> Leo Sher also proposed that seasonal mood changes may contribute to the increased incidence and mortality of coronary artery disease in winter. Depression is associated with increased incidence, morbidity, and mortality of coronary artery disease.

*Coronary artery disease shows a winter peak and summer trough in incidence and mortality.<ref> Sher L., 2001 </ref> Leo Sher also proposed that seasonal mood changes may contribute to the increased incidence and mortality of coronary artery disease in winter. Depression is associated with increased incidence, morbidity, and mortality of coronary artery disease.

*“Seasonal affective disorder” is a condition where depression in the winter and fall alternate with non-depressive periods in the spring and summer. The degree to which seasonal changes affect mood, energy, sleep, appetite, food preference, or the wish to socialize with other people has been called "seasonality." Recent studies have demonstrated that seasonal mood changes are related to the genetic factors. It means that people may have genetically‐determined sensitivity to seasons.     

*“Seasonal affective disorder” is a condition where depression in the winter and fall alternate with non-depressive periods in the spring and summer. The degree to which seasonal changes affect mood, energy, sleep, appetite, food preference, or the wish to socialize with other people has been called "seasonality." Recent studies have demonstrated that seasonal mood changes are related to the genetic factors. It means that people may have genetically‐determined sensitivity to seasons.     

*Jaiswal et al, 2011, in a clinical survey<ref> Jaiswal Rahul et al, 2011 </ref> found a significant relation between seasonal variation and prevalence of some diseases viz. ''jwara'' (viral fever), ''amlapitta'' (acid peptic disorders), ''tamaka shvasa'' (bronchial asthma), ''pratishyaya'' (rhinitis) and ''sirashula'' (''pittaja sirashula'' and ''ardhavabhedaka'', migraine). They also observed that there is seasonal variation in the state of ''agni'' and bala strength) of the person, as stated by our ancient seers.  

*Jaiswal et al, 2011, in a clinical survey<ref> Jaiswal Rahul et al, 2011 </ref> found a significant relation between seasonal variation and prevalence of some diseases viz. [[jwara]] (viral fever), [[amlapitta]] (acid peptic disorders), [[tamaka shvasa]] (bronchial asthma), [[pratishyaya]] (rhinitis) and [[shirashula]] ([[pitta]] dominant [[shirashula]] and [[ardhavabhedaka]], migraine). They also observed that there is seasonal variation in the state of [[agni]] and [[bala]] (strength) of the person, as stated by our ancient seers.  

*Nathani et al, 2013, in a clinical research<ref> Nathani Neeru et al, 2013 </ref> found that maximum number of patients of ''tamaka shvasa'' (bronchial asthma) were registered in winter seasons (''hemanta'' and ''shishira''), ''vasanta'' and ''varsha''. These seasons were the predominant period of asthma attack in majority of cases. In maximum number of cases the attack of ''tamaka shvasa'' gets precipitated by intake of ''kapha'' and ''vata'' vitiating ''sheeta, guru, madhura'' and ''amla rasa'' predominant ''ahara'' like ice-cream, cold drink, cold water, fruit juices, curd, sweets, rice, pickle, salad with lemon etc. in all seasons.  

*Nathani et al, 2013, in a clinical research<ref> Nathani Neeru et al, 2013 </ref> found that maximum number of patients of [[tamaka shvasa]] (bronchial asthma) were registered in winter seasons ([[hemanta]] and [[shishira]]), [[vasanta]] and [[varsha]]. These seasons were the predominant period of asthma attack in majority of cases. In maximum number of cases the attack of [[tamaka shvasa]] gets precipitated by intake of [[kapha]] and [[vata]] vitiating [[sheeta]], [[guru]], [[madhura]] and [[amla]] [[rasa]] predominant [[ahara]] like ice-cream, cold drink, cold water, fruit juices, curd, sweets, rice, pickle, salad with lemon etc. in all seasons.  

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