HammerFit-45 (HF45) is a 45-minute coached high-intensity interval training class and one of the most popular sessions on the Hammer’s Gym timetable, for good reason. HIIT is among the most researched training methods in fitness, and the findings are consistent: it delivers results in a fraction of the time of traditional cardio. Here are six HIIT class benefits the evidence supports, and what to expect when you walk into your first HF45 in Nunawading.
1. A big calorie burn in a short time
Studies comparing 30 minutes each of HIIT, weight training, running and cycling have found HIIT burns roughly 25 to 30 per cent more calories than the other formats. In practice that means you can match the energy expenditure of a much longer steady session in a third of the time, which is exactly why HF45 fits into a lunch break or before work. See our comparison of HIIT vs LISS.
2. Your metabolism stays elevated for hours
Much of HIIT’s benefit arrives after you have finished. Research shows high-intensity work raises your metabolic rate for hours post-exercise, the afterburn effect known as EPOC, and shifts your body toward using fat for fuel during recovery. One study found that a few minutes of sprint intervals increased 24-hour energy expenditure as much as 30 minutes of continuous running.
3. It helps you lose fat
In one 12-week study, people doing HIIT three times a week for 20 minutes lost around two kilograms of body fat with no changes to their diet, and a broad body of research shows HIIT reduces body fat and waist circumference despite the small time commitment. The effect is largest for people who are overweight, and larger still when you pair the training with sensible nutrition; see calorie deficit vs surplus.
4. You may gain muscle
Alongside fat loss, HIIT can increase muscle mass, mostly in the muscles doing the work, typically the trunk and legs, and mostly in people who were less active beforehand. Because HF45 includes loaded movements such as kettlebell swings, thrusters and sled work, it builds more muscle than a pure cardio interval session. For anyone worried about bulk, the research is reassuring: HIIT produces lean, athletic muscle, not size.
5. Lower heart rate and blood pressure
Research consistently shows HIIT reduces resting heart rate and blood pressure, particularly in people who are overweight. In one study, eight weeks of HIIT on a stationary bike lowered blood pressure as much as continuous endurance training in adults with high blood pressure, with the HIIT group training three times a week for 20 minutes against the endurance group’s four sessions of 30. Some researchers have found HIIT may reduce blood pressure even more than the commonly recommended moderate-intensity exercise. If you have a diagnosed condition, talk to your doctor before starting and tell your coach.
6. Better blood sugar control
A review of around 50 studies found that HIIT programs of under 12 weeks reduce blood sugar and improve insulin resistance more than continuous exercise, which suggests high-intensity training is particularly valuable for anyone at risk of type 2 diabetes. Studies in people already living with type 2 diabetes have also shown improvements in blood sugar control. Read how HIIT helps fight diabetes.
What to expect in HammerFit-45
A coached warm-up, then 30 to 35 minutes of interval blocks combining bodyweight movements, kettlebells, dumbbells, sleds, ropes and cardio machines, followed by a cool-down. Every exercise has an easier and a harder option, so beginners and athletes train side by side, and the coach adjusts loads and pace for you. Expect to be breathless, expect to laugh at least once, and expect to feel great an hour later. Read the benefits of group fitness classes for why the coached format matters.
How often should you do HIIT?
Two or three sessions a week is ideal for most people, with at least a day between them and some strength or easy cardio on the other days. More than that tends to leave you too fatigued to train well. Our balanced gym program guide shows where HF45 fits in a week.
Try HammerFit-45
HF45 classes run throughout the week at Hammer’s Gym in Nunawading, no bookings required, and they are included in membership. Check the timetable for times, claim a free one-day trial and come and see why it is one of our most popular classes. We are minutes from Mitcham, Blackburn, Box Hill and Doncaster; see reception for any extra info.