Time-restricted eating decreases norepinephrine, but not epinephrine or muscle sympathetic nerve activity, in healthy middle-aged adults

Time-restricted eating (TRE) is a dietary approach that restricts calories within a specific window of time each day. Implementing TRE at midlife, a time in the adult lifespan prior to overt disease, may be beneficial as a preventative strategy against disease later in life. However, there is limited evidence of effects of TRE in humans, especially on autonomic cardiovascular control and at midlife. Thus, the purpose of this study was to identify the effects of TRE on autonomic cardiovascular control measures in healthy middle-aged adults by assessing resting muscle sympathetic nerve activity (MSNA) and circulating catecholamines (norepinephrine, NE; epinephrine, Epi) before and after a 5-week TRE intervention. We hypothesized that MSNA, NE, and Epi would decrease from pre- to post-TRE. Twenty-nine healthy middle-aged adults (12M/17F; age: 54 ± 5 yrs) participated in 5 weeks of TRE where meals were consumed within a 10-hour window and ≥ 2 hours prior to bedtime. Dietary intake was measured 3 days per week via a diet log. Resting heart rate (HR) and blood pressure (BP) were measured using a 3-lead electrocardiogram and an automated brachial cuff, respectively. MSNA was measured via microneurography and reported as burst frequency (BF; bursts/min) and burst incidence (BI; bursts/100 heart beats), and catecholamines were measured following venipuncture. Paired t-tests were used to evaluate differences from pre- and post-TRE. Following 5 weeks of TRE, systolic BP (SBP) was reduced (Pre: 126 ± 10 mmHg; Post: 122 ± 10 mmHg; p = 0.024), however there were no other differences pre- to post-TRE for any other resting vital of interest (p > 0.051). Interestingly, NE decreased post-TRE (Pre: 22.3 ± 15.5 ng/mL; Post: 12.3 ± 6.5 ng/mL; p = 0.004), while Epi (Pre: 1.1 ± 0.5 ng/mL; Post: 0.9 ± 0.6 ng/mL; p = 0.163), MSNA BF (Pre: 29 ± 11 bursts/min; Post: 25 ± 12 bursts/min; p = 0.257), and MSNA BI (Pre: 47 ± 18 bursts/100 heart beats; Post: 42 ± 19 bursts/100 heart beats; p = 0.376) did not change post-TRE. A 5-week TRE intervention reduced circulating NE without observable changes in Epi or MSNA. We observed a reduction in SBP, which could be attributable to reduced NE, but future studies are needed to further investigate TRE and its impact on autonomic cardiovascular control. Funding: AHA (191PLOI34680015) NIH (T32HL007936) This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.