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Correlations between altered body temperature and depression have been reported in small samples; greater confidence in these associations would provide a rationale for further examining potential mechanisms of depression related to body temperature regulation. We sought to test the hypotheses that greater depression symptom severity is associated with (1) higher body temperature, (2) smaller differences between body temperature when awake versus asleep, and (3) lower diurnal body temperature amplitude. Data collected included both self-reported body temperature (using standard thermometers), wearable sensor-assessed distal body temperature (using an off-the-shelf wearable sensor that collected minute-level physiological data), and self-reported depressive symptoms from > 20,000 participants over the course of ~ 7 months as part of the TemPredict Study. Higher self-reported and wearable sensor-assessed body temperatures when awake were associated with greater depression symptom severity. Lower diurnal body temperature amplitude, computed using wearable sensor-assessed distal body temperature data, tended to be associated with greater depression symptom severity, though this association did not achieve statistical significance. These findings, drawn from a large sample, replicate and expand upon prior data pointing to body temperature alterations as potentially relevant factors in depression etiology and may hold implications for development of novel approaches to the treatment of major depressive disorder.

Despite decades of research on yoga and depression, subjective experiences of participants in these studies have rarely been reported, and never in individuals receiving heated yoga for depression. We examined patient-reported qualitative findings from an 8-week randomized controlled trial of heated yoga for depression. Eighty medically healthy participants with moderate-to-severe depression were randomized to 8 weeks of at least twice-weekly heated yoga classes, derived from Bikram yoga, or a waitlist control. Fifty-seven participants received a clinician-administered exit interview at intervention completion/study withdrawal. The exit interview assessed: (1) how participants felt immediately following the heated yoga sessions (acute effects), (2) what they liked or found helpful about heated yoga over the 8-week intervention (positive effects), and (3) what they disliked/did not find helpful over the 8-week intervention (negative effects). Qualitative data were analyzed using thematic analysis. Acute improvements in depressive symptoms (i.e., immediately following yoga) were the most commonly reported (n = 44, 77.2%), followed by overall positive effects on depressive symptoms (i.e., over the course of the 8-week intervention; n = 33, 57.9%), including improvements in sleep (n = 10, 17.5%), energy (n = 13, 22.8%), mood (n = 18, 31.6%), motivation (n = 2, 3.5%), and concentration/decision-making (n = 5, 8.8%). Overall negative effects (i.e., over the course of the 8-week intervention) included dislike of various aspects of the intervention (n = 19, 33.3%), such as instruction (n = 7, 12.3%), difficulty (n = 7, 12.3%), repetitiveness (n = 3, 5.3%), class length (n = 2, 3.5%), and boredom (n = 7, 12.3%). Most participants reported both overall positive and negative effects (n = 37, 64.9%). Of the rest, 19 (33.3%) reported only overall positive effects, and 1 (1.8%) reported only overall negative effects. Most participant experiences were positive. Negative effects were less common and primarily involved dislike of different aspects of the heated yoga. The findings support strong acceptability and subjective improvement in depressive symptoms in depressed individuals.