Time-Restricted Eating Improves Blood Pressure but not Cardiovagal Baroreflex Sensitivity in Healthy Middle-Aged Adults

Time-restricted eating (TRE) is a low-cost lifestyle intervention that has been shown to reduce day- and nighttime blood pressure (BP), however previous work has mainly been done in animal models. Further, little research has investigated the effects of TRE on markers of cardiovascular health and BP regulation (i.e. baroreflex sensitivity; BRS), especially in humans. With midlife being a crucial time in which the risk of cardiovascular disease increases, understanding the effects of lifestyle interventions like TRE on middle-aged adults may provide insight on preventative strategies against disease. Therefore, the purpose of this study was to investigate the effects of TRE on cardiovascular variables and cardiovagal BRS (cvBRS) in middle-aged healthy adults. We hypothesized that TRE would reduce BP and increase cvBRS. Twenty-nine (12M/17F) healthy, middle-aged adults (56±5 years) were assessed before and after a 5-week TRE intervention. Outside of the lab, 24-hour ambulatory BP monitoring (ABPM) was performed using an inflatable arm cuff to provide nighttime, daytime, and overall BP. Morning surge index (MSI) was calculated to assess peak BP upon waking. Upon arrival to the lab in the morning following an overnight fast, cardiovascular variables were assessed including supine beat-to-beat BP and stroke volume (SV) via finger plethysmography as well as heart rate (HR) via 3-lead ECG. cvBRS was measured by obtaining the slope of the relationship between systolic BP (SBP) and R-R intervals during Phase IV of the Valsalva maneuver. Results from ABPM after 5 weeks of TRE showed nighttime SBP (Pre: 107±10 mmHg; Post: 104±8 mmHg) and diastolic BP (DBP; Pre:63±5 mmHg; Post: 62±6 mmHg) decreased (p<0.05 for both). The decrease in daytime SBP (Pre: 128±10 mmHg; Post: 125±12 mmHg; p=0.055), overall SBP (Pre: 121±9 mmHg; Post: 119±11 mmHg; p=0.054), and MSI (Pre: 20.4±9.2; Post: 16.8±9.8; p=0.069) did not reach significance. There were no differences in daytime DBP (Pre: 79±7 mmHg; Post: 78±8 mmHg; p=0.175) or overall DBP (Pre: 74±6 mmHg; Post: 73±7 mmHg; p=0.130). Results from the lab visit after 5 weeks of TRE showed supine beat-to-beat SBP decreased (Pre: 126±10 mmHg; Post: 122±10 mmHg; p<0.05) but the decrease in DBP did not reach significance (Pre: 78±6 mmHg; Post: 77±6 mmHg; p=0.078). There were no differences in SV (Pre: 92±19 mL; Post: 91±26 mL; p=0.380), HR (Pre: 57±8 bpm; Post: 56±8 bpm; p=0.213) or cvBRS (Pre: 9.2±5.8 ms/mmHg; Post: 10.2±6.0 ms/mmHg; p=0.123) at rest. A 5-week TRE intervention affects BP, especially reducing nighttime BP, without observable effects on daytime HR, SV, or cvBRS. Future work should consider other BP regulatory mechanisms such as sympathetic activity when investigating effects of TRE. American Heart Association (191PLOI34680015; JNB) and the National Institutes of Health (T32HL007936; SHAGM). This abstract was presented at the American Physiology Summit 2025 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.