High-intensity interval training induces a modest systemic inflammatory response in active, young men

Figures & data

Figure 1 Protocol schematic. Subjects completed eight total visits over a 3-week period, including a pre-training testing session and HIIT familiarization session, six HIIT sessions, and a post-training testing session. Blood was collected during HIIT session 1 and HIIT session 6 for the analysis of inflammatory cytokines and chemokines.

Abbreviation: HIIT, high-intensity interval training.

Table 1 Inflammatory cytokines not significantly altered by HIIT

	Rest		Immediately post		15 min post		30 min post		45 min post		P-value
	HIIT #1	HIIT #6	HIIT #1	HIIT #6	HIIT #1	HIIT #6	HIIT #1	HIIT #6	HIIT #1	HIIT #6	Interaction	Time point	Training
GM-CSF (pg/mL)	1.01±1.20	1.05±1.12	1.76±2.47	1.10±1.91	0.98±1.13	0.38±0.37	0.61±0.38	0.68±0.61	0.31±0.15	0.77±0.91	0.382	0.172	0.484
IFNγ(pg/mL)	1.49±1.52	1.63±2.11	3.51±5.85	3.87±7.86	2.74±5.22	0.84±0.35	1.18±0.92	1.42±1.74	1.00±0.86	1.76±2.76	0.518	0.286	0.266
IL-1β(pg/mL)	0.57±0.40	0.46±0.32	0.65±0.48	0.56±0.43	0.78±1.10	0.43±0.27	0.43±0.33	0.43±0.33	0.38±0.21	0.41±0.22	0.425	0.205	0.195

Note: Values are mean ± SD (n=7).

Abbreviations: GM-CSF, granulocyte macrophage-colony-stimulating factor; HIIT, high-intensity interval training; IFNγ, interferon-γ, IL-1β, interleukin-1β; HIIT #1, HIIT session #1; HIIT #6, HIIT session #6.

Figure 2 Serum inflammatory cytokines in response to an acute bout of HIIT. IL-6 (A), IL-8 (B), MCP-1 (C), TNF-α (D), and IL-10 (E) concentrations were measured before and immediately (Imm), 15, 30, and 45 minutes after completion of an acute bout of HIIT exercise (at a workload equivalent to 100% of VO₂max) on a cycle ergometer during the first and sixth HIIT exercise sessions.

Notes: Open bars, first HIIT session; filled bars, sixth HIIT session. Data are reported as mean ± SD; n=7.*indicates significantly different from at rest.

Abbreviations: HIIT, high-intensity interval training; IL, interleukin; MCP, monocyte chemotactic protein; SD, standard deviation; TNF, tumor necrosis factor; VO₂max, peak oxygen uptake.

Table 2 Physiological variables before and after two weeks of HIIT exercise training

	PRE	POST	% Change	P-value
VO2max (mL/kg/min)	49.2±2.6	49.6±2.0	0.8%	0.481
Peak power (Watts)	324±40	339±39*	4.6%	0.007
Watts at 100% VO2max	314±45	326±35	3.8%	0.190
RPE after interval 8	20±1	17±3*	−15.0%	0.028
HR after interval 8 (bpm)	190±10	184±12*	−3.2%	0.014

Notes: Values are mean ± SD (n=8).

* indicates significantly different from PRE.

Abbreviations: HIIT, high-intensity interval training; PRE, before two weeks of HIIT exercise training; POST, after two weeks of HIIT exercise training; VO₂max, peak oxygen uptake.