How much can our health behaviours affect blood pressure?
Everyone responds differently, but this chart gives averages from clinical studies for people who have high blood pressure. Typically the higher your blood pressure, the larger the response you can expect to get.
For simplicity, it lists just systolic blood pressure (the bigger top number), but the diastolic would go down too, a smaller amount.
| Intervention (Note) | Approximate impact on systolic blood pressure in people with hypertension (mm Hg) |
| DASH eating pattern (1) | -11 |
| Sodium reduction (1) | -5-6 |
| Increase potassium (1, 2) | -4-5 |
| 30-60 minutes of moderate intensity exercise 4-7 days per week (3) | -7.4 |
| Dynamic resistance exercise (weight lifting), 90–150 min/week (1, 4) | -4 |
| Isometric resistance exercise (eg. plank) (1, 4) | -5 |
| Moderation in alcohol intake (1) | -4 |
| Weight loss (1, 5) | -5 (-1 for every 1 kg loss) |
| Stress management (3,6) | -9.7 with multicomponent relaxation techniques -15.2 with individualized cognitive stress management |
Notes:
- Source – the American Heart Association / American College of Cardiology 2017 High Blood Pressure Clinical Practice Guideline (table 15)
- Not an explicit focus in our challenge but following the DASH eating pattern will help.
- Source: Hypertension Canada Guidelines
- Outside of our scope.
- We won’t focus on that because we don’t have a weight-loss intervention that is safe and effective in the long run. We’re focusing on what we can more readily control.
- From the guidelines: “The key to this approach is tailoring the intervention to the patient’s needs… Strategies include increasing awareness of stressors and stress responses, re-evaluating negative life events, communications skills training (e.g., marital communication and assertiveness training), development of problem-solving skills, management of negative emotions (e.g., anger and anxiety) and techniques for decreasing sympathetic arousal (e.g., relaxation exercises).”
The stress management piece is clearly beyond what we can accomplish in our challenge, but I wanted to raise your awareness of this important consideration.
What is DASH?
Aside from a well-designed, individualized stress management intervention, one of the most impactful things you can do for your blood pressure is follow the DASH eating pattern. DASH stands for “Dietary Approaches to Stop Hypertension.”
It was first studied in the 1990’s when researches gave 459 volunteers food that either:
- Followed the DASH pattern
- Was similar to the typical American diet (control)
- Was similar to the typical American diet but richer in fruit and vegetables.
The food was planned so that people didn’t gain or lose weight, and the sodium level was the same in all three groups.
After just 14 days, blood pressure was significantly reduced in people eating the DASH food. (The fruit and vegetable group improved, but not quite as much.)
There have been more studies of DASH-like approaches with various twists, and I’ll talk about them as we go along with the challenge. But the core habits include plenty of fruit, vegetables, whole grains, legumes, nuts, seeds, milk products, and smaller amounts of meat, fish, chicken, eggs, high-sugar foods, and oils. In fact, the recently released update to Canada’s Food Guide was designed with DASH in mind.
The theory behind DASH is that while excessive amounts of the mineral sodium can increase blood pressure over time, the minerals potassium, magnesium, and calcium seem to have the opposite effect. The higher levels of fibre and protein may also play a role.