Neutrophil and Monocyte Bactericidal Responses to 10 Weeks of Low‐Volume High‐Intensity Interval or Moderate‐Intensity Continuous Training in Sedentary Adults

Abstract

Neutrophils and monocytes are key components of the innate immune system that undergo age-associated declines in function. This study compared the impact of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) on immune function in sedentary adults. Twenty-seven (43 ± 11 years) healthy sedentary adults were randomized into ten weeks of either a HIIT (>90% maximum heart rate) or MICT (70% maximum heart rate) group training program. Aerobic capacity (VO2peak), neutrophil and monocyte bacterial phagocytosis and oxidative burst, cell surface receptor expression, and systemic inflammation were measured before and after the training. Total exercise time commitment was 57% less for HIIT compared to that for MICT while both significantly improved VO2peak similarly. Neutrophil phagocytosis and oxidative burst and monocyte phagocytosis and percentage of monocytes producing an oxidative burst were improved by training similarly in both groups. Expression of monocyte but not neutrophil CD16, TLR2, and TLR4 was reduced by training similarly in both groups. No differences in systemic inflammation were observed for training; however, leptin was reduced in the MICT group only. With similar immune-enhancing effects for HIIT compared to those for MICT at 50% of the time commitment, our results support HIIT as a time efficient exercise option to improve neutrophil and monocyte function.

Acute and chronic effects of High Intensity Interval Training on inflammatory and oxidative stress markers of postmenopausal obese women

“…Evaluated the effect of HIIT in obese women with type 2 diabetes and found an improvement in inflammatory profile through the decreased expression of TLR‐4 and TLR‐2 in the cell surface of lymphocytes and monocytes after 2 weeks of training. Furthermore, HIIT induces immune stimulatory actions such as the increasing potential for CCR5‐mediated chemotaxis and improvements in oxidative burst and phagocytosis of stimulated‐leukocytes …”

Effects of Exercise on Chemotherapy Completion and Hospitalization Rates: The OptiTrain Breast Cancer Trial

“…Moreover, muscle strength has been shown to be negatively associated with days of having fever . In healthy individuals, both moderate‐intensity as well as high‐intensity interval aerobic training has been shown to lead to an improved neutrophil function , and recent findings show that resistance training can increase the number of neutrophils and lymphocytes after exercise .…”

There is limited existing evidence to support the common assumption that strenuous endurance exercise bouts impair immune competency

“…A recent example is sprint-interval exercise, also referred to as High Intensity Interval Exercise (HIIE), which, as might be expected, stimulates T cell and Natural Killer cell trafficking, but responses are larger following a continuous and sustained exercise stimulus [33]. Other studies have shown that frequent HIIE (or High Intensity Interval Training; HIIT) does not compromise mucosal immunity [34] and that both HIIT and continuous training similarly improve innate immune cell function at rest [35]. Exploring the immunological effects of different exercise modes has merit for improving understanding of immune function, especially if the optimal mode of exercise is yet to be established for particular groups (e.g.…”