Effect of exercise modality and intensity on post-exercise interleukin-6 and hepcidin levels
- Authors: Sim, Marc , Dawson, Brian , Landers, Grant , Swinkels, Dorine , Tjalsma, Harold , Trinder, Debbie , Peeling, Peter
- Date: 2013
- Type: Text , Journal article
- Relation: International Journal of Sport Nutrition and Exercise Metabolism Vol. 23, no. 2 (2013), p. 178-186
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- Description: The effect of exercise modality and intensity on Interleukin-6 (IL-6), iron status, and hepcidin levels was investigated. Ten trained male triathletes performed 4 exercise trials including low-intensity continuous running (L-R), low-intensity continuous cycling (L-C), high-intensity interval running (H-R), and high-intensity interval cycling (H-C). Both L-R and L-C consisted of 40 min continuous exercise performed at 65% of peak running velocity (vVO2peak) and cycling power output (pVO2peak), while H-R and H-C consisted of 8 x 3-min intervals performed at 85% vVO2peak and pVO2peak. Venous blood samples were drawn pre-, post-, and 3 hr postexercise. Significant increases in postexercise IL-6 were seen within each trial (p < .05) and were significantly greater in H-R than L-R (p < .05). Hepcidin levels were significantly elevated at 3 hr postexercise within each trial (p < .05). Serum iron levels were significantly elevated (p < .05) immediately postexercise in all trials except L-C. These results suggest that, regardless of exercise mode or intensity, postexercise increases in IL-6 may be expected, likely influencing a subsequent elevation in hepcidin. Regardless, the lack of change in postexercise serum iron levels in L-C may indicate that reduced hemolysis occurs during weight-supported, low-intensity activity.
Oral contraception does not alter typical post-exercise interleukin-6 and hepcidin levels in females
- Authors: Sim, Marc , Dawson, Brian , Landers, Grant , Swinkels, Dorine , Tjalsma, Harold , Yeap, Bu , Trinder, Debbie , Peeling, Peter
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Science and Medicine in Sport Vol. 18, no. 1 (2015), p. 8-12
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- Description: OBJECTIVES: The post-exercise interleukin-6 (IL-6) and hepcidin response was investigated during the hormone-deplete and hormone-replete phases of an estradiol and progestogen regulated oral contraceptive cycle (OCC). DESIGN: Counterbalanced, repeated measures cross-over study. METHODS: Ten active female monophasic oral contraceptive pill (OCP) users completed two 40 min treadmill running trials at 75% of their pre-determined peak oxygen uptake velocity (vVO2peak). These trials were randomly performed in two specific phases of the OCC: (a) Day 2-4, representing a hormone-free withdrawal period (D-0); (b) Day 12-14, representing the end of the first week of active hormone therapy (D+7). Venous blood samples were drawn pre-, post- and 3h post-exercise. RESULTS: In both trials, serum IL-6 was significantly elevated (p<0.05) immediately post-exercise, while serum hepcidin was significantly elevated (p<0.05) 3h post-exercise, with no significant differences recorded between trials. CONCLUSIONS: These findings suggest that exercise performed during the different phases (D-0 vs. D+7) of a monophasic OCP regulated cycle does not alter exercise induced IL-6 or hepcidin production. As such, future studies looking to investigate similar variables post-exercise, may not need to 'control' for different phases of the OCC, provided participants are current monophasic OCP users.
Iron status and the acute post-exercise hepcidin response in athletes
- Authors: Peeling, Peter , Sim, Marc , Badenhorst, Claire , Dawson, Brian , Govus, Andrew , Abbiss, Chris , Swinkels, Dorine , Trinder, Debbie
- Date: 2014
- Type: Text , Journal article ,
- Relation: PLoS One Vol. 9, no. 3 (2014), p. e93002
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- Description: This study explored the relationship between serum ferritin and hepcidin in athletes. Baseline serum ferritin levels of 54 athletes from the control trial of five investigations conducted in our laboratory were considered; athletes were grouped according to values <30 mug/L (SF<30), 30-50 mug/L (SF30-50), 50-100 mug/L (SF50-100), or >100 mug/L (SF>100). Data pooling resulted in each athlete completing one of five running sessions: (1) 8 x 3 min at 85% vVO2peak; (2) 5 x 4 min at 90% vVO2peak; (3) 90 min continuous at 75% vVO2peak; (4) 40 min continuous at 75% vVO2peak; (5) 40 min continuous at 65% vVO2peak. Athletes from each running session were represented amongst all four groups; hence, the mean exercise duration and intensity were not different (p>0.05). Venous blood samples were collected pre-, post- and 3 h post-exercise, and were analysed for serum ferritin, iron, interleukin-6 (IL-6) and hepcidin-25. Baseline and post-exercise serum ferritin levels were different between groups (p<0.05). There were no group differences for pre- or post-exercise serum iron or IL-6 (p>0.05). Post-exercise IL-6 was significantly elevated compared to baseline within each group (p<0.05). Pre- and 3 h post-exercise hepcidin-25 was sequentially greater as the groups baseline serum ferritin levels increased (p<0.05). However, post-exercise hepcidin levels were only significantly elevated in three groups (SF30-50, SF50-100, and SF>100; p<0.05). An athlete's iron stores may dictate the baseline hepcidin levels and the magnitude of post-exercise hepcidin response. Low iron stores suppressed post-exercise hepcidin, seemingly overriding any inflammatory-driven increases.
The effects of carbohydrate ingestion during endurance running on post-exercise inflammation and hepcidin levels
- Authors: Sim, Marc , Dawson, Brian , Landers, Grant , Wiegerinck, Erwin , Swinkels, Dorine , Townsend, Mary-Anne , Trinder, Debbie , Peeling, Peter
- Date: 2012
- Type: Text , Journal article
- Relation: European Journal of Applied Physiology Vol. 112, no. 5 (2012), p. 1889-1898
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- Description: The effect of carbohydrate (CHO) consumption during prolonged endurance running on post-exercise inflammation and hepcidin levels was investigated. Eleven well-trained male endurance athletes completed a graded exercise test, followed by two experimental running trials in a randomized order. The two experimental trials consisted of a 90 min run at 75% of the peak oxygen uptake velocity (vVO(2peak)), while consuming a solution with either 6% CHO or a placebo (PLA) equivalent at 3 ml kg(-1) every 20 min. Serum interleukin-6 (IL-6), free hemoglobin (Hb), haptoglobin (Hp), hepcidin and iron parameters were assessed throughout the post-run recovery period. Serum iron and IL-6 were significantly elevated immediately post-run in both CHO and PLA (p = 0.05), with no differences between trials. Serum-free Hb increased and Hp decreased significantly immediately post-run in both conditions (p = 0.05). Serum soluble transferrin receptor levels were significantly below the baseline at 3 and 24 h post-run in both conditions (p = 0.05). Serum hepcidin concentration recorded 3 h post-run in both conditions was significantly elevated (p = 0.05), and had returned to the baseline by 24 h post-run (p = 0.05). The use of a 6% CHO solution at 3 ml kg(-1) 20 min(-1) during endurance running did not attenuate the inflammatory response and subsequent increase in serum hepcidin levels during the post-run recovery period.
Interleukin-6 and Hepcidin levels during hormone-deplete and hormone-replete phases of an oral contraceptive cycle : A pilot study
- Authors: Sim, Marc , Dawson, Brian , Landers, Grant , Swinkels, Dorine , Wiegerinck, Erwin , Yeap, Bu Beng , Trinder, Debbie , Peeling, Peter
- Date: 2017
- Type: Text , Journal article
- Relation: Annals of Nutrition and Metabolism Vol. 70, no. 2 (2017), p. 100-105
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- Description: Background: In the past, elevated estradiol levels were reported to downregulate the iron regulatory hormone hepcidin, thereby potentially improving iron metabolism. As estrogen plays a role in regulating the menstrual cycle and can influence the cytokine interleukin-6 (IL-6; a hepcidin up-regulator), this investigation examined the effects of estradiol supplementation achieved by the use of a monophasic oral contraceptive pill (OCP) on IL-6, hepcidin levels and iron status during the hormone-deplete versus hormone-replete phases within an oral contraceptive cycle (OCC). Methods: Fifteen healthy female OCP users were recruited and provided a venous blood sample on 2 separate mornings during a 28-day period. These included (a) days 2-4 of the OCC, representing a hormone-free withdrawal period (WD); (b) days 12-14 of the OCC, representing the end of the first week of active hormone therapy (AHT). Results: IL-6 and hepcidin levels were not significantly different at WD and AHT. Serum ferritin was significantly higher (p = 0.039) during AHT as compared to WD. Conclusions: Fluctuations in OCP hormones (estradiol and/or progestogen) had no effect on basal IL-6 and hepcidin levels in young women. Nevertheless, elevated ferritin levels recorded during AHT may indicate that OCP hormones can positively influence iron stores within an OCC despite unchanged hepcidin levels. © 2017 S. Karger AG, Basel.
Iron regulation in athletes: exploring the menstrual cycle and effects of different exercise modalities on hepcidin production
- Authors: Sim, Marc , Dawson, Brian , Landers, Grant , Trinder, Debbie , Peeling, Peter
- Date: 2014
- Type: Text , Journal article
- Relation: International Journal of Sport Nutrition and Exercise Metabolism Vol. 24, no. 2 (2014), p. 177-187
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- Description: The trace element iron plays a number of crucial physiological roles within the body. Despite its importance, iron deficiency remains a common problem among athletes. As an individual's iron stores become depleted, it can affect their well-being and athletic capacity. Recently, altered iron metabolism in athletes has been attributed to postexercise increases in the iron regulatory hormone hepcidin, which has been reported to be upregulated by exercise-induced increases in the inflammatory cytokine interleukin-6. As such, when hepcidin levels are elevated, iron absorption and recycling may be compromised. To date, however, most studies have explored the acute postexercise hepcidin response, with limited research seeking to minimize/attenuate these increases. This review summarizes the current knowledge regarding the postexercise hepcidin response under a variety of exercise scenarios and highlights potential areas for future research-such as: a) the use of hormones though the female oral contraceptive pill to manipulate the postexercise hepcidin response, b) comparing the use of different exercise modes (e.g., cycling vs. running) on hepcidin regulation.
A seven day running training period increases basal urinary hepcidin levels as compared to cycling
- Authors: Sim, Marc , Dawson, Brian , Landers, Grant , Swinkels, Dorine , Tjalsma, Harold , Wiegerinck, Erwin , Trinder, Debbie , Peeling, Peter
- Date: 2014
- Type: Text , Journal article
- Relation: Journal of the International Society of Sports Nutrition Vol. 11, no. 1 (2014), p. 1-9
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- Description: BACKGROUND: This investigation compared the effects of an extended period of weight-bearing (running) vs. non-weight-bearing (cycling) exercise on hepcidin production and its implications for iron status. METHODS: Ten active males performed two separate exercise training blocks with either running (RTB) or cycling (CTB) as the exercise mode. Each block consisted of five training sessions (Day 1, 2, 4, 5, 6) performed over a seven day period that were matched for exercise intensity. Basal venous blood samples were obtained on Day 1 (D1), and on Recovery Days 3 (R3) and 7 (R7) to assess iron status, while basal and 3 h post-exercise urinary hepcidin levels were measured on D1, D2, D6, as well as R3 and R7 (basal levels only) for each condition. RESULTS: Basal urinary hepcidin levels were significantly elevated (p = 0.05) at D2, R3 and R7 as compared to D1 in RTB. Furthermore, 3 h post-exercise urinary hepcidin levels on D1 were also significantly higher in RTB compared to CTB (p = 0.05). In CTB, urinary hepcidin levels were not statistically different on D1 as compared to R7. Iron parameters were not significantly different at D1 compared to R3 and R7 during both conditions. CONCLUSIONS: These results suggest that basal hepcidin levels may increase over the course of an extended training program, especially if a weight-bearing exercise modality is undertaken. However, despite any variations in hepcidin production, serum iron parameters in both RTB and CTB were unaffected, possibly due to the short duration of each training block. In comparing running to cycling, non-weight-bearing activity may require more training sessions, or sessions of extended duration, before any significant changes in basal hepcidin levels appear. Chronic elevations in hepcidin levels may help to explain the high incidence of iron deficiency in athletes.