20
views
0
recommends
+1 Recommend
1 collections
    0
    shares

      To submit to the journal, please click here

      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Human circadian phase–response curves for exercise

      research-article

      Read this article at

      ScienceOpenPublisherPMC
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Key points

          • Exercise elicits circadian phase‐shifting effects, but additional information is needed.

          • The phase–response curve describing the magnitude and direction of circadian rhythm phase shifts, depending on the time of the zeigeber (time cue) stimulus, is the most fundamental chronobiological tool for alleviating circadian misalignment and related morbidity.

          • Fifty‐one older and 48 young adults followed a circadian rhythms measurement protocol for up to 5.5 days, and performed 1 h of moderate treadmill exercise for 3 consecutive days at one of eight times of the day/night.

          • Temporal changes in the phase of 6‐sulphatoxymelatonin (aMT6s) were measured from evening onset, cosine acrophase, morning offset and duration of excretion. Significant phase–response curves were established for aMT6 onset and acrophase with large phase delays from 7:00 pm to 10:00 pm and large phase advances at both 7:00 am and from 1:00 pm to 4:00 pm. Delays or advances would be desired, for example, for adjustment to westward or eastward air travel, respectively.

          • Along with known synergism with bright light, the above PRCs with a second phase advance region (afternoon) could support both practical and clinical applications.

          Abstract

          Although bright light is regarded as the primary circadian zeitgeber, its limitations support exploring alternative zeitgebers. Exercise elicits significant circadian phase‐shifting effects, but fundamental information regarding these effects is needed. The primary aim of the present study was to establish phase–response curves (PRCs) documenting the size and direction of phase shifts in relation to the circadian time of exercise. Aerobically fit older ( n = 51; 59–75 years) and young adults ( n = 48; 18–30 years) followed a 90 min laboratory ultrashort sleep–wake cycle (60 min wake/30 min sleep) for up to 5½ days. At the same clock time on three consecutive days, each participant performed 60 min of moderate treadmill exercise (65–75% of heart rate reserve) at one of eight times of day/night. To describe PRCs, phase shifts were measured for the cosine‐fitted acrophase of urinary 6‐sulphatoxymelatonin (aMT6s), as well as for the evening rise, morning decline and change in duration of aMT6s excretion. Significant PRCs were found for aMT6s acrophase, onset and duration, with peak phase advances corresponding to clock times of 7:00 am and from 1:00 pm to 4:00 pm, delays from 7:00 pm to 10:00 pm, and minimal shifts around 4:00 pm and 2:00 am. There were no significant age or sex differences. The amplitudes of the aMT6s onset and acrophase PRCs are comparable to expectations for bright light of equal duration. The phase advance to afternoon exercise and the exercise‐induced PRC for change in aMT6s duration are novel findings. The results support further research exploring additive phase‐shifting effects of bright light and exercise and health benefits.

          Key points

          • Exercise elicits circadian phase‐shifting effects, but additional information is needed.

          • The phase–response curve describing the magnitude and direction of circadian rhythm phase shifts, depending on the time of the zeigeber (time cue) stimulus, is the most fundamental chronobiological tool for alleviating circadian misalignment and related morbidity.

          • Fifty‐one older and 48 young adults followed a circadian rhythms measurement protocol for up to 5.5 days, and performed 1 h of moderate treadmill exercise for 3 consecutive days at one of eight times of the day/night.

          • Temporal changes in the phase of 6‐sulphatoxymelatonin (aMT6s) were measured from evening onset, cosine acrophase, morning offset and duration of excretion. Significant phase–response curves were established for aMT6 onset and acrophase with large phase delays from 7:00 pm to 10:00 pm and large phase advances at both 7:00 am and from 1:00 pm to 4:00 pm. Delays or advances would be desired, for example, for adjustment to westward or eastward air travel, respectively.

          • Along with known synergism with bright light, the above PRCs with a second phase advance region (afternoon) could support both practical and clinical applications.

          Related collections

          Most cited references59

          • Record: found
          • Abstract: found
          • Article: not found

          Shift work, risk factors and cardiovascular disease.

          The literature on shift work, morbidity and mortality from cardiovascular disease, and changes in traditional risk factors is reviewed. Seventeen studies have dealt with shift work and cardiovascular disease risk. On balance, shift workers were found to have a 40% increase in risk. Causal mechanisms of this risk via known cardiovascular risk factors, in relation to circadian rhythms, disturbed sociotemporal patterns, social support, stress, behavior (smoking, diet, alcohol, exercise), and biochemical changes (cholesterol, triglycerides, etc) are discussed. The risk is probably multifactorial, but the literature has focused on the behavior of shift workers and has neglected other possible causal connections. In most studies methodological problems are present; these problems are related to selection bias, exposure classification, outcome classification, and the appropriateness of comparison groups. Suggestions for the direction of future research on this topic are proposed.
            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Light therapy for seasonal and nonseasonal depression: efficacy, protocol, safety, and side effects.

            Bright light therapy for seasonal affective disorder (SAD) has been investigated and applied for over 20 years. Physicians and clinicians are increasingly confident that bright light therapy is a potent, specifically active, nonpharmaceutical treatment modality. Indeed, the domain of light treatment is moving beyond SAD, to nonseasonal depression (unipolar and bipolar), seasonal flare-ups of bulimia nervosa, circadian sleep phase disorders, and more. Light therapy is simple to deliver to outpatients and inpatients alike, although the optimum dosing of light and treatment time of day requires individual adjustment. The side-effect profile is favorable in comparison with medications, although the clinician must remain vigilant about emergent hypomania and autonomic hyperactivation, especially during the first few days of treatment. Importantly, light therapy provides a compatible adjunct to antidepressant medication, which can result in accelerated improvement and fewer residual symptoms.
              Bookmark
              • Record: found
              • Abstract: found
              • Article: not found

              The effects of prior light history on the suppression of melatonin by light in humans.

              We investigated the impact of light exposure history on light sensitivity in humans, as assessed by the magnitude of the suppression of melatonin secretion by nocturnal light. The hypothesis was that following a week of increased daytime bright-light exposure, subjects would become less sensitive to light, and that after a week of restriction to dimmer light they would become more sensitive. During the bright week, subjects (n = 12) obtained 4.3 +/- 0.4 hr of bright light per day (by going outside and using light boxes indoors). During the dim week, they wore dark goggles (about 2% light transmission) when outside during daylight and spent 1.4 +/- 0.9 hr per day outside. Saliva samples were obtained every 30 min for 7 hr in dim light (<15 lux) on two consecutive nights (baseline and test night) at the end of each week. On the test night, 500 lux was presented for 3 hr in the middle of the collection period to suppress melatonin. There was significantly more suppression after the dim week compared with after the bright week (to 53 versus 41% of the baseline night values, P < 0.05). However, there were large individual differences, and the difference between the bright and dim weeks was most pronounced in seven of the 12 subjects. Possible reasons for these individual differences are discussed, including the possibility that 1 wk was not long enough to change light sensitivity in some subjects. In conclusion, this study suggests that the circadian system's sensitivity to light can be affected by a recent change in light history.
                Bookmark

                Author and article information

                Contributors
                shawn.youngstedt@asu.edu
                Journal
                J Physiol
                J. Physiol. (Lond.)
                10.1111/(ISSN)1469-7793
                TJP
                jphysiol
                The Journal of Physiology
                John Wiley and Sons Inc. (Hoboken )
                0022-3751
                1469-7793
                18 March 2019
                15 April 2019
                18 March 2019
                : 597
                : 8 ( doiID: 10.1113/tjp.2019.597.issue-8 )
                : 2253-2268
                Affiliations
                [ 1 ] College of Nursing and Health Innovation and College of Health Solutions Arizona State University Phoenix AZ USA
                [ 2 ] Phoenix VA Health Care System Phoenix AZ USA
                [ 3 ] Department of Psychiatry University of California San Diego CA USA
                [ 4 ] Center for Circadian Biology University of California San Diego CA USA
                Author notes
                [*] [* ] Corresponding author S. D. Youngstedt: College of Nursing and Health Innovation, Arizona State University, 550 N. 3rd St Phoenix, AZ 85004, USA. Email: shawn.youngstedt@ 123456asu.edu

                Author information
                https://orcid.org/0000-0002-2318-8179
                Article
                TJP13444
                10.1113/JP276943
                6462487
                30784068
                46f12fdb-5c08-4dca-958b-2478874a2434
                © 2019 The Authors. The Journal of Physiology published by John Wiley & Sons Ltd on behalf of The Physiological Society

                This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

                History
                : 07 August 2018
                : 28 January 2019
                Page count
                Figures: 7, Tables: 3, Pages: 16, Words: 10807
                Funding
                Funded by: NHLBI
                Award ID: HL095799
                Award ID: HL61280
                Categories
                Research Paper
                Neuroscience
                Editor's Choice
                Custom metadata
                2.0
                tjp13444
                15 April 2019
                Converter:WILEY_ML3GV2_TO_NLMPMC version:5.6.2.1 mode:remove_FC converted:15.04.2019

                Human biology
                prc,ultra‐short sleep wake schedule,circadian time,phase shift,phase advance,phase delay,6‐sulphatoxymelatonin

                Comments

                Comment on this article