RESULTS	Relative to caffeine , there were further acute increases in systolic and diastolic blood pressure at 30 min among those drinking green tea [ 5.5 mmHg ( 95 % CI -1.4 to 12.4 ) and 3.1 mmHg ( 95 % CI -0.1 to 6.3 ) , respectively ] and black tea [ 10.7 mmHg ( 95 % CI 4.0 to 17.4 ) and 5.1 mmHg ( 95 % CI 1.8 to 8.4 ) , respectively ] .\