The effect of acute vs chronic magnesium supplementation on exercise and recovery on resistance exercise, blood pressure and total peripheral resistance on normotensive adults.
Study Goal
The researchers aimed to assess the effect of oral magnesium supplementation on resistance exercise performance and vascular response after intense exercise, comparing acute (1-week) and chronic (4-week) loading strategies.
Results Summary
Acute magnesium supplementation (1-week) improved bench press performance by 7.7% on day 1 and prevented performance decline on day 2, while chronic supplementation (4-week) led to a 32.1% decrease in performance on day 2. Both loading strategies reduced systolic blood pressure, but only acute loading reduced diastolic blood pressure and total peripheral resistance.
Population
13 participants in a randomized, double-blind, crossover, placebo-controlled study.
Effective Dosage
300 mg/d elemental magnesium.
Duration
1 week (acute) or 4 weeks (chronic).
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
Magnesium supplementation | decrease | blood pressure | - | up to 12 mmHg | has previously shown reductions | #1 |
Magnesium supplementation | increase | performance gains in resistance exercise | - | - | positive relationship | #2 |
300 mg/d elemental magnesium (1 week loading strategy - A) | increase | Bench press | n=13 | 7.7% | showed a significant increase | #3 |
300 mg/d elemental magnesium (1 week loading strategy - A) | no change | performance | n=13 | - | showed no decrease | #4 |
300 mg/d elemental magnesium (4 week loading strategy - Chr) | decrease | performance | n=13 | 32.1% | showed a decrease | #5 |
300 mg/d elemental magnesium (1 week loading strategy - A) | decrease | post-exercise systolic blood pressure (SBP) | n=13 | - | was significantly lower | #6 |
300 mg/d elemental magnesium (4 week loading strategy - Chr) | decrease | post-exercise systolic blood pressure (SBP) | n=13 | - | was significantly lower | #7 |
300 mg/d elemental magnesium (1 week loading strategy - A) | decrease | Diastolic blood pressure (DBP) | n=13 | - | showed significant decreases | #8 |
300 mg/d elemental magnesium (4 week loading strategy - Chr) | no change | Diastolic blood pressure (DBP) | n=13 | - | no changes | #9 |
300 mg/d elemental magnesium (1 week loading strategy - A) | decrease | Total peripheral resistance (TPR) | n=13 | - | reduced | #10 |
300 mg/d elemental magnesium (4 week loading strategy - Chr) | increase | Total peripheral resistance (TPR) | n=13 | - | showing an increase | #11 |
300 mg/d elemental magnesium (4 week loading strategy - Chr) | no change | Total peripheral resistance (TPR) | n=13 | - | no change | #12 |
300 mg/d elemental magnesium (1 week loading strategy - A) | increase | bench press | n=13 | - | showed improvement | #13 |
300 mg/d elemental magnesium (4 week loading strategy - Chr) | decrease | bench press | n=13 | - | showing a decrease | #14 |
300 mg/d elemental magnesium (1 week loading strategy - A) | decrease | DBP | n=13 | - | showed reductions | #15 |
300 mg/d elemental magnesium (4 week loading strategy - Chr) | decrease | DBP | n=13 | - | showed reductions | #16 |
300 mg/d elemental magnesium (1 week loading strategy - A) | decrease | TPR | n=13 | - | showed greater reductions | #17 |
BACKGROUND: Magnesium supplementation has previously shown reductions in blood pressure of up to 12 mmHg. A positive relationship between magnesium supplementation and performance gains in resistance exercise has also been seen. However, no previous studies have investigated loading strategies to optimise response. The aim of this study was to assess the effect of oral magnesium supplementation on resistance exercise and vascular response after intense exercise for an acute and chronic loading strategy on a 2-day repeat protocol. METHODS: The study was a randomised, double-blind, cross-over design, placebo controlled 2 day repeat measure protocol (n = 13). Intense exercise (40 km time trial) was followed by bench press at 80% 1RM to exhaustion, with blood pressure and total peripheral resistance (TPR) recorded. 300 mg/d elemental magnesium was supplemented for either a 1 (A) or 4 (Chr) week loading strategy. Food diaries were recorded. RESULTS: Dietary magnesium intake was above the Reference Nutrient Intake (RNI) for all groups. Bench press showed a significant increase of 7.7% (p = 0.031) [corrected] for A on day 1. On day 2 A showed no decrease in performance whilst Chr showed a 32.1% decrease. On day 2 post-exercise systolic blood pressure (SBP) was significantly lower in both A (p = 0.0.47) and Chr (p = 0.016) groups. Diastolic blood pressure (DBP) showed significant decreases on day 2 solely for A (p = 0.047) with no changes in the Chr. TPR reduced for A on days 1 and 2 (p = 0.031) with Chr showing an increase on day 1 (p = 0.008) and no change on day 2. CONCLUSION: There was no cumulative effect of Chr supplementation compared to A. A group showed improvement for bench press concurring with previous research which was not seen in Chr. On day 2 A showed a small non-significant increase but not a decrement as expected with Chr showing a decrease. DBP showed reductions in both Chr and A loading, agreeing with previous literature. This is suggestive of a different mechanism for BP reduction than for muscular strength. TPR showed greater reductions with A than Chr, which would not be expected as both interventions had reductions in BP, which is associated with TPR.