Unexpected changes in blood pressure and hematological parameters among fasting and nonfasting workers during Ramadan in Indonesia

Eur J Clin Nutr. 2006 Jul;60(7):877-81. doi: 10.1038/sj.ejcn.1602393. Epub 2006 Feb 8.


Objective: To examine the effect of Ramadan fasting on basic hematological parameters, in addition to the effects on body weight and blood pressure of fasters and nonfasters.

Design, setting, and subjects: One hundred male outdoor workers at a vehicle terminal in a city in East Java were recruited for this study. Anthropometric measurements and blood sampling were conducted on two separate occasions, just before the start of Ramadan and in the third week of the month of Ramadan (October-November 2004). The degree of subjective compliance with Ramadan fasting (complete, partial, or none) was evaluated using a questionnaire.

Results: The mean body mass index (BMI) of the fasting group was, as expected, significantly lower at the second sampling period, and the decrease in BMI correlated significantly with decreased blood pressure in this group. The blood pressure was also reduced in the partial fasting and nonfasting groups, which was an unexpected result. While red blood cell production was suppressed, as evidenced by lower levels of hemoglobin, red blood cell (RBC), and packed cell volume (PCV) at the second sampling, the subjects were normocytic and normochromic, based on normal mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) levels.

Conclusions: These results indicate that, regardless of fasting status, blood pressure is lower and RBC production is suppressed in subjects during the Ramadan period. These findings should be taken into account when evaluating the effects of Ramadan on the general population. To avoid the adverse effects of anemia, increased intake of iron-rich foodstuffs is recommended during the Ramadan month, regardless of fasting practice.

MeSH terms

  • Adolescent
  • Adult
  • Analysis of Variance
  • Anemia / epidemiology
  • Anemia / etiology
  • Blood Pressure / physiology*
  • Body Mass Index
  • Body Weight / physiology*
  • Erythrocyte Count*
  • Fasting* / blood
  • Fasting* / physiology
  • Hemoglobins / analysis
  • Humans
  • Indonesia
  • Islam*
  • Male
  • Middle Aged


  • Hemoglobins