Acute Effects of Different Sprint Intervals on Blood Pressure, Heart Rate Variability, Lactate and Performance Responses in Physically Active Men
Authors: Sant'Ana Leandro de Oliveira , Scartoni Fabiana Rodrigues , Martins da Cruz Thiago , de Souza Ribeiro Aline Aparecida , dos Reis Natália Rodrigues , Vieira da Silva João Guilherme , Campos Yuri de Almeida Costa , da Silva Araujo Gleisson , Monteiro Estêvão Rios , Machado Sérgio , Castro Antônio Paulo , da Silva Novaes Jefferson , Vianna Jeferson Macedo 
Published: June 2022

Background:
Sprint interventions can be an excellent alternative for promoting positive adaptations to health and performance.

Objectives:
To verify the responses of different intervals between sprints in blood pressure, heart rate variability, lactate, and performance responses in physically active men.

Methods:
Ten male runners participated in the present study, trained in street running with at least one year of experience and a maximum of 3 years, with training frequency of at least two times and at the most four times weekly sessions, all participants without any kind of restrictions that could hinder the interventions—performing three sprint sessions (10 x 30m all out). Participants visited the laboratory on four occasions for ten consecutive days, with an interval of 48 hours between each visit. The first visit was intended to familiarize the participants with all experimental procedures. The remaining three visits were used to carry out the experimental protocols. At each visit, resting values ​​of blood pressure (BP), heart rate variability (HRV), and lactate variables were collected. After rest collections, each participant completed the following experimental conditions: a) 10 sprint series (all-out) of 30 meters with 20 seconds of recovery (S 20), b) 10 sprint series (all-out) of 30 meters with 30 seconds of recovery (S 30) and c) 10 sprint series (all-out) of 30 meters with 40 seconds of recovery (S 40). After each protocol, the lactate values ​​were collected 2 minutes and 30 seconds after the end of the sprints; BP was collected 60 minutes after the intervention (Post-10, Post-20, Post-30, Post-40, and Post- 50). After the blood pressure (BP) data was determined, the mean arterial pressure (MBP) was calculated using the formula MBP = SBP + (DBP X 2) / 3. The HRV was collected between 50 and 60 minutes after the end of the sprint session.

Results:
The study observed significant differences in the lactate variable for the comparison in the post and pre moments for all experimental conditions (S 20, S 30, and S 40) (p<0.001). Besides, significant differences were observed in effort perception for S 20 and S 30 from the sixth sprint (p<0.05). At S 40, significant discrepancies in effort perception started from the fifth sprint (p <0.05). No other significant differences were observed for BP (systolic, diastolic and mean) for all post-pre periods. Still in BP, in a post (intra) analysis, the conditions S 20 and S 40 demonstrated greater capacity for recovery of BP, suggesting a possible greater parasympathetic capacity. For HRV and sprint performance, no difference was found (p <0.05).

Conclusion:
The present study demonstrated that different recovery intervals did not reflect significant differences in hemodynamic, autonomic, lactate responses, and active individuals' performance submitted to sprint sessions. This study applied a protocol (10 x 30 m all out) with different recovery times (20, 30, and 40 seconds), and which, given this experiment, can serve as a training strategy (for health or performance) at different levels of physical conditioning.