Authors' replyBMJ 1994; 308 doi: https://doi.org/10.1136/bmj.308.6937.1164 (Published 30 April 1994) Cite this as: BMJ 1994;308:1164
- Martin Middeke,
- Joachim Schrader
- Chief doctor, Reha-Zentrum Spreewald, D-03096 Burg/Spreewald, Germany Chief doctor, St Josefs-Hospital, D-49661 Cloppenburg, Germany.
EDITOR,--We agree with Michael J Stewart that the definition of day and night will have a considerable influence on the calculated variation in blood pressure between day and night. The effect of the frequency of measurement, on the other hand, is much less, as long as the measurements are not taken too infrequently ( > 40 minutes) at night. Our experience has shown that the period 2200 to 0600 is compatible with the actual sleep …