Evidence that meal fat content does not impact hemodynamic reactivity to or recovery from repeated mental stress tasks

The magnitude (reactivity) and duration (recovery) of hemodynamic stress responses are predictive of cardiovascular risk, and fat intake has been shown to enhance hemodynamic reactivity to psychological stress tasks. The objective of this study was to determine the impact of a high-fat meal (HFM) on the magnitude and stability of hemodynamic stress reactivity and recovery. This was assessed by: (i) the peak changes from baseline to during stress for heart rate (HR); mean, systolic, and diastolic blood pressure; cardiac output; and total peripheral resistance; and (ii) the residual arousal in hemodynamic parameters at 2 points post-stress ("early" and "late" recovery). On different days, 10 healthy males (aged 23.2 ± 3.3 years) consumed either a HFM (54 g fat) or low-fat meal (LFM; 0 g fat) (∼1000 calories each), followed by 4 hourly 10-min stress tasks (mental arithmetic and speech tasks). Pre-stress (baseline) parameters did not differ between HFM and LFM conditions (all P > 0.05). Plasma triglycerides were greater following the HFM versus the LFM (P = 0.023). No reactivity or recovery parameters differed between meals (all P > 0.05). Stress reactivity and recovery parameters were stable over the 4 stress tasks (main effects of time, all P > 0.05), with the exception of HR (P < 0.05). Contrary to previous reports, meal fat content did not impact hemodynamic reactivity to laboratory stressors. These data also provide the first evidence that meal fat content does not impact hemodynamic recovery from repeated mental stress tasks.