Magnesium supplementations effect on blood pressure has been well documented but is inconsistent.Previous studies have found variations in reduction from 12mmHg to no reduction.Physical activity, although having a positive chronic effect on blood pressure can be detrimental at the point of activity.We set out to look at blood pressure on aerobic and resistance/power exercise along with performance during rest and recovery periods.Pilot work showed significant decrease in resting systolic blood pressure (SBP) by 8.9mmHg (P=0.01) with magnesium intervention.After a 5 minutes recovery from a 30 minute maximal cycle, the control group were 2.36% below resting measures of SBP whereas the experimental group were 4.30% lower than resting measures.There was no change in performance indicators.The data was then analysed by habitual dietary magnesium intake dividing groups into high and low intake (high =≥ RNI of 300mg.d, low =≤ RNI of 300mg.d), a greater reduction in SBP was observed in the low magnesium group at rest (P=0.05).A further study investigated peak and mean power, with a 30 second Wingate Anaerobic Test (WAnT test).There was a significant decrease (P<0.05) in SBP during the 30 minutes recovery postWAnT in the Mg condition compared to the placebo condition resulting in a 5% lower mean SBP over the 30 minutes recovery.However, there was no significant difference in diastolic blood pressure between the placebo and the Mg condition during the 30 minutes recovery post-WAnT.Our recent meta-analysis looked at magnesium supplementations effect on blood pressure and identified 22 trials with 23 sets of data (n=1173) fitting our inclusion criteria of magnesium supplementation and inclusion of control or placebo group.Dose ranged from 120mg to 720mg magnesium with a mean dose of 398mg.Combining all data an overall effect of 0.36 and 0.32 for DBP and SBP respectively was observed with a greater effect seen in the crossover trials.Effect size increased in line with increased dosage.Only limited trials accounted for serum and urinary magnesium or habitual dietary magnesium.Future work will be looking towards effect of habitual dietary magnesium intake on blood pressure and serum magnesium levels and effect of supplementation in both hypertensive and normotensive population.